Microsoft SQL Server 2012 comes in 3 main editions, two testing \ developers editions and one free edition.
The SQL datacentre edition has been cancelled and new BI version has been added.
|High Availability, large scale datacentres and data warehouse, max number of cores ,AlwaysOn , Unlimited Virtualization
|Good for small and SMB deployments, support up to 16 cores, basic High Avaliablity with only two nods, Up to 4 CPU and 64GB Ram, One VM
|BI functions like reporting and Analytics, Power View, PowerPivot, Max number of cores for BI processing all standard edition functions
|All enterprise edition functionality but can be used only for development and testing
|For service providers that host clients internet facing websites, support 4 CPU and 64GB of RAM
|Free, One CPU, 1GB RAM, and 10GB Storage
Note: The new Enterprise Edition is similar to the old Datacentre edition in SQL 2008