Windows Server 2012 Datacenter and Standard are technically identical – there is absolutely no difference between them with regard technical capabilities.
The only difference is the virtualisation rights included with the license (two VMs for Standard and as many as you like for Datacenter). So if you’re virtualising you should be using Datacentre – that’s the only decision you have to make. As a rule of thumb, once you get to around five VMs you should have gone with Datacentre.
You can download Windows Server 2012 form here. And read all about it here.
Windows Server 2012 Essentials has not released to manufacture (RTM) yet, it is still in a Release Candidate stage. It is targeted at Small and Medium businesses with less than 25 PCs. It is an ideal first server that works seamlessly with Office 365. You can download the RC here and learn all about it here.
Windows Server 2012 Foundation is only available pre-installed onto a new server from an Original Equipment Manufacturer (OEM). It is designed for organisations with up to 15 users who need a great general purpose (and economical) server.
Licensing and pricing info for all editions is here.
If you need to evaluate Windows Server 2012 (or any other OS for that matter), using the Infrastructure as a Service (IaaS) role in Windows Azure is probably the easiest, quickest and cheapest way to go.
Start by visiting the Windows Azure website.
If you don’t have a subscription, you can sign up for a 90 day free trial.
Signing up takes no more that a minute or two (you will need a credit card to do this – but Microsoft will not charge you a cent).
Next you need to sign up for the preview of the IaaS role (you’ll be warned that charges may be incurred – they won’t unless you authorise them).
Now you can enter the portal
And create a new virtual machine
Give your virtual machine a name, an administrative password and a size (Small is fine for your first evaluation).
Give it a DNS name (must be unique – yourname.cloudapp.net) and pick North Europe as the Region (that’s the Dublin datacentre).
You can ignore the Availability Set for now (you can learn more about that if you decide to learn Windows Azure).
Click the tick and your virtual machine will provision itself. This normally takes around 12-15 minutes (it starts and stops a couple of times as it configures itself).
When it’s finished, click on Connect and you will remote Desktop Connection (RDP) into your new Windows Server 2012 VM.