UPDATED: June 2013

I decided to collect my own short list of hotfixes for that I have recommended for an Exchange 2010/Windows 2008 R2 environment. 
  NOTE: This does not include security hotfixes (WSUS) and is NOT an official list of hotfixes or build recommendation - this is my list of hotfixes that I have recommended for newly deployed Exchange environments as a means to prevent known issues from occurring.

Exchange 2010 Hotfixes
  Exchange 2010 Service Pack 3 – http://support.microsoft.com/kb/2808208
  KB2803727 Update Rollup1 for Exchange Server 2010 Service Pack 3 - http://support.microsoft.com/kb/2803727


Office 2010 Hotfixes
  Office 2010 Service Pack 1 - http://support.microsoft.com/kb/2460049
  KB2597090 Description of the Outlook 2010 update: February 2013 - http://support.microsoft.com/kb/2597090
  KB2553391 Description of the Outlook 2010 hotfix package: December 11, 2012 - http://support.microsoft.com/kb/2553391
  KB2832226 Office 2010 cumulative update for April 2013 - http://support.microsoft.com/kb/2832226

Office 2013 Hotfixes 
  KB2738013 Description of the Outlook 2013 Update: April 2013 - http://support.microsoft.com/kb/2738013

Office for Mac 2011 Hotfixes 
  KB2830450 Description of the Microsoft Office for Mac 2011 14.3.4 Update - http://support.microsoft.com/kb/2830450

Base Windows 2008 R2 SP1 Hotfix
KB 2775511 – An Enterprise Hotfix rollup for Windows Server 208 R2 SP1 – http://support.microsoft.com/kb/2775511


Windows 2008 R2 Post-SP1 Hotfixes 
  KB2754704 http://support.microsoft.com/kb/2754704 -- MPIO
  KB2471472 http://support.microsoft.com/kb/2471472 -- NDIS
  KB2769369 http://support.microsoft.com/kb/2769369 -- WIN32SPL
  KB2494016 http://support.microsoft.com/kb/2494016 -- CSVFILTER  
  KB2578113 http://support.microsoft.com/kb/2578113 -- CLUSRES 
  KB2614892 http://support.microsoft.com/kb/2614892 -- MOUNTMGR  
  KB2536275 http://support.microsoft.com/kb/2536275 -- SYS  
  KB2619234 http://support.microsoft.com/kb/2619234 -- RPCHTTP
  KB2724197 http://support.microsoft.com/kb/2724197 -- Kernel   
  KB2779069 http://support.microsoft.com/kb/2779069 -- CLUSSVC 
  KB2699780 http://support.microsoft.com/kb/2699780 -- Registry 
* Updated from previous hotfix notification release 


Lync Server 2010 Hotfixes
  Updates Resource Center for Lync  - http://technet.microsoft.com/en-us/lync/gg131945

NOTE: If you cannot download the hotfix from the KB, then first, determine if you really need that hotfix and if so, consider contacting MSFT support for that build or look for another, related hotfix with similar files and build.

Have Fun...
Doug