As many times used in our daily business, we’re used to ask for “Build number” rather than “Service Pack or Patch level”. Because of some confusion of the customers and for transparency I’ll provide here a list of the most relevant Build numbers and its related KB Numbers.  Have a look here for the MOSS/WSS Build Numbers ;-)

Used abbreviations:   MSF2010* = SharePoint Foundation (WSSv4);    SPS2010* = SharePoint Server 2010

Note:
The bits of RTM version are shown in central admin page with Build number “14.0.4762.1000” but it’s actually “14.0.4763.1000” - So no worry about ;-)
In case of early publishing, some KB article might not be available right away while the download links already working. Please consider, that delay’s in publishing the according KB articles will be expected!

Jump list:

• Update sequence of SharePoint 2010 packages
• Links and Resources
• Language Packs
• Background Info on CU's
• Filter Packs
• Project Server
• SP1 and June 2011 CU
• The mystery behind SharePoint 2010 Patching
• Slipstream Installations with updates included
• Support Life Cycle for SharePoint Products
  • SharePoint Foundation 2010
  • SharePoint Server 2010

Important:

• For June 2010, we have no FULL server (Uber) Package (CU), so there are several separate patches which have to be installed one-by-one!
• In the June 2010 CU1 KB983497 we have fixed several “user profile sync and import issues”. For the complete list of the June 2010 CU1 patches see also here.
• In the Oct. 2010 CU a regression was detected but the problem is fixed and the packages are republished now as build 14.0.5128.5003
• In the  Dec. 2010 CU, a regression was found. "You cannot create an AD DS synchronization connection ... after Dec.CU 2010 installed...(KB 2490381)"
• Latest SharePoint 2010 Service Pack 1 information!
• If you also have Project Server 2010 in your farm, please get the full server package for project server from here: http://technet.microsoft.com/en-us/projectserver/gg176680

Last Update: 2012-05-25

Note !

)** -> Marked with this is a post SP1 Hotfix! SP1 is mandatory to install this CU!

R! -> This marks updates with detected Regressions!

Note:
Due to early posting, sometimes the KB-articles and Descriptions for the updates are not directly working!
So please expect some delay in final publishing of the KB's!  But the Download Links should work almost immediately!

Note for SP1:
Microsoft SharePoint Server 2010 Service Pack 1 (SP1) provides the latest updates for SharePoint Server 2010.
This service pack includes two main categories of fixes:

• Previously unreleased fixes that were made specifically for this service pack. In addition to general product fixes, these fixes include improvements in stability, performance, and in security.
• All the public updates that were released through June 2011, and all the cumulative updates that were released through April 2011.
• Description of SharePoint 2010 SP1: http://support.microsoft.com/kb/2460045
• Technical Details:  http://support.microsoft.com/kb/2532120
• Known issues when you install SP1: http://support.microsoft.com/kb/2532126

For clarification: 

If you are currently on any Build stage prior or equal  April 2011 CU, please perform the update as follows:

1. Install the SP1 packages for SharePoint Foundation on all Servers in Farm
2. Install the according Language packs (if applicable) on all Servers in Farm
3. Install the SP1 packages for SharePoint Server on all Servers in Farm
4. Install the according Language packs (if applicable) on all Servers in Farm for each language installed!
5. Install the Office Web Apps SP1 (if applicable)
6. Install the SharePoint Foundation June 2011 CU on top on on all Servers in Farm
7. Install the according Language packs (if applicable) on all Servers in Farm for each language installed!
8. Install the SharePoint Server June 2011 CU on top on on all Servers in Farm
9. Install the according Language packs (if applicable) on all Servers in Farm for each language installed!

The SharePoint 2010 Products Configuration Wizard or "psconfig –cmd upgrade –inplace b2b -wait” should be run once on every server in the farm following the final update installed.

Q:  
Is it true that installing only the server packages would be sufficient as they contain the foundation packages anyway?

A:  
We recommend installing the SharePoint Foundation 2010 packages followed by the SharePoint Server 2010 packages to ensure all binaries are properly updated as a best practice; 
however, Server packages will include the Foundation package so they could be installed independently.
The June CU does not include all of the files included in Service Pack 1 so should be installed following Service Pack 1.  In order to ensure everything is up to date, you will need to install both packages.

Note for June 2011 CU:   
Re-released due to some known problems, described in the according KB articles to the hotfixes!
See more here: http://blogs.technet.com/b/stefan_gossner/archive/2011/07/12/june-2011-cu-for-sharepoint-2010-has-been-re-released.aspx

If not having downloaded the latest version for June CU (14.0.6106.5002), please get the fresh bits again and install them on top to ensure that you have the fixed packages in place!

New FIM bits implemented!
With the June 2011 CU package, there is also a new FIM release (ForeFront Identitiy Manager aka "missclient.exe") published.
Where before, the FIM showed up with version 4.0.2450.11, you'll after installing June 2011 CU notice, that it will come up now in version 4.0.2450.34 yet.

Uninstall or Disable Office Web Apps? Use this guide to chose whether Office web apps might be required or should be uninstalled.

Also related:  http://blogs.technet.com/b/steve_chen/archive/2011/06/07/3433939.aspx

Posts by CAPES:
SharePoint 2010 SP1 and the June Cumulative Update for SharePoint 2010

Office 2010 Service Pack 1:   Five Common questions regarding the Service Pack

Note:
With the February 2011 CU we also will have a SharePoint Designer 2010 hotfix package available!
KB 2496947 Description of the SharePoint Designer 2010 hotfix package, February 22, 2011

Download link:  http://support.microsoft.com/hotfix/KBHotfix.aspx?kbnum=2496947&kbln=en-us

Background Information of Cumulative Update (CU)

Cumulative update packages for Microsoft SharePoint Foundation 2010 and Microsoft SharePoint Server 2010 containing hotfixes for the issues that were fixed since the release of SharePoint foundation and SharePoint Server 2010. They are sometimes also called “Uber Package”.

After applying the preceding updates, run the SharePoint Products and Technologies Configuration Wizard or “psconfig –cmd upgrade –inplace b2b -wait” in command line.
This needs to be done on all servers in the farm with SharePoint 2010 installed.
As usually, you should start with the server, hosting the central admin and finishing it there, after all other servers has been updated as well!
The other servers now can run the psconfig wizard in parallel (on MOSS we had to run them sequentially, one by one).

Recommended Update sequence of packages:

As commented by the escalation folks at Microsoft, it should be sufficient to apply only the SharePoint Server2010 “Uber” packages (aka MOSS14; SPS2010) as these contains the SharePoint Foundation packages (aka WSSv4; MSF2010) as well. But still there is a recommendation to stick on the "old common" approach...

Resource: SharePoint Server 2010, SharePoint Foundation 2010 - Updates | TechNet

Extract:
Best practice (this is my opinion and is the result of daily support challenges and issues, that are related to this process!)

For any given build you may find that it is not necessary to install a SharePoint Foundation 2010 update before you install a SharePoint Server 2010 update. This flexibility in the installation sequence is part of the software update system design. However, there might be times where it is necessary to remove this flexibility in order to properly fix a specific issue.

I personally recommend that you always install SharePoint Foundation 2010 patches before installing SharePoint Server 2010 patches. This best practice ensures that you will always be successful when installing updates and keeps you on the save side.

 Install Order:
- start with the Foundation update,
- then run the Psconfig wizard
- reboot if prompted
- install now the server packages
- then run the Psconfig wizard again
- reboot once more if prompted
- check for errors on logs!
- check on Central admin page -> Upgrade and Migration -> Upgrade status / product and patch installation status

repeat this for each server in farm.

As per this Link now: http://technet.microsoft.com/en-us/sharepoint/ff800847.aspx 
"...it is no longer necessary to install the SharePoint Foundation cumulative update and then install the SharePoint Server cumulative update."

Well yes, its true and you can do so if it is more applicable for your Environment. but I still may recommend to follow as above to keep the best consistency for any updates as well for future.
But yeah, if you don't want to go the extra step, for common CU updates, the server package (SharePoint) or the full Project Server package suffices all your needs, ;-)

Slipstreamed installation and updates:
How to create a slipstreamed installation source:
http://technet.microsoft.com/en-us/library/cc261890(office.12).aspx

Be careful when you use SharePoint slipstreamed installations!   - by Jie Li
http://blogs.msdn.com/b/opal/archive/2011/07/06/be-careful-when-you-use-slipstreamed-sharepoint-installation-files.aspx 

Project Server 2010:  
Updates for Project Server 2010
Blog of Brian Smith
Project Server Admin blog

Download SharePoint Server 2010 with Project Server February 2011 CU (KB 2475879 ) 
Download SharePoint Server 2010 with Project Server April 2011 CU  (KB 2512801)

Download SharePoint Server 2010 with Project Server February 2012 CU

Language Packs:
Deploy language packs (SharePoint Server 2010)
Deploy language packs (SharePoint Foundation 2010)
Install Language Packs for SharePoint Server 2010
Install available language template packs (SharePoint Foundation 2010)
Install available language template packs (SharePoint Server 2010)
Install SharePoint 2010 Language Pack on Windows 7  

 Note:
Installing language packs on the Web servers
After you install the necessary language files on the Web servers, you can install the language packs. Language packs are available as individual downloads (one download for each supported language). If you have a server farm environment and you are installing language packs to support multiple languages, you must install the language packs on each of the Web servers.

Important:
The language pack is installed in its native language. For example, the Russian language pack executable file is in Russian...

SharePoint Foundation 2010 language packs are not required for SharePoint Server 2010 (http://technet.microsoft.com/en-us/library/cc262108.aspx)

 
Filter Packs:
Microsoft Office 2010 Filter Packs

Additional or related resources:

• Updates for SharePoint 2010 Products
• Updates for Project Server 2010
• Updates for Enterprise Search Products
• Update Center for Microsoft Office, Office Servers, and Related Products
• Software updates overview (SharePoint Server 2010)
• Please see also my post All about updating MOSS or more information on the Install order and what to be considered when installing updates for MOSS 2007/WSSv3

Please send me a comment, if you find a mistake or dead link here,
Thx, Steve