SQL Server 2008 R2, it comes with new editions and lot of new features, also supporting the SQL Azure & PowerPivot with Excel 2010. The first info about SQL Server release date (21/04/2010) was on Brent Ozar (blog | twitter) post including info of the new features.
Except Enterprise & Standard Edition, SQL Server 2008 R2 has two new premium editions and they are DataCenter & Parallel Data Warehouse. These two version are especially for the needs of large scale DataCentres and Data Warehouses.
- Supports more than 8 processors and up to 256 logical processors for highest levels of scale
- Supports memory limits up to OS maximum
- High-scale complex event processing with SQL Server StreamInsight
- etc, etc
Parallel Data Warehouse
- 10s to 100s TBs enabled by MPP (massively parallel processing) architecture
- Integration with SSIS, SSRS, and SSAS
About the price list and for further info about all SQL Server 2008 R2 versions are here