With Windows Server 2012 and 2012 R2, Microsoft decided to focus its licensing all over virtualization. Of course, you can choose not to virtualize, but there are benefits in the virtual environments.
The first big change was the retirement of the Enterprise Edition, leaving the Standard and Datacenter Editions as the available choices. Again, there are other options for small businesses, but they are not the focus here. With only two options available, customers have now a simple scenario to choose.
The other big change is that the Standard and Datacenter Editions are exactly the same regarding technical features. It means that all features are available on both editions, such as cluster, RDS, and so on. Also, both editions have the same support for hardware. In conclusion, the only difference (apart from licensing) between the Standard and Datacenter Editions is the Windows Server logo.
The question you might have now is...