We can expect the RTM release of Service Pack 2 for SQL Server 2005 very very soon.  In the meantime, please take a look at the updated readme file (dated 9th Jan 2007) 'Whats new in SQL Server 2005 SP2' which is available here: http://download.microsoft.com/download/2/b/5/2b5e5d37-9b17-423d-bc8f-b11ecd4195b4/WhatsNewSQL2005SP2.htm (this has continually been updated in line with the fixes and changes which are being made).

Here are some of my favourite changes/additions:

1. Vardecimal compression
2. SSIS no longer required for maintenance plans
3. Custom reports (and also changes to the SSMS disk usage report to improve performance)
4. Reporting Services integration with MOSS 2007
5. Much better setup and install experience (SP1 was a little unpredictable)
6. I also like the Data Mining add-in for Excel and Visio 2007 (although this is provided as a Feature Pack download and is not native to SP2) - check it out here: http://www.microsoft.com/downloads/details.aspx?FamilyID=aa0c2623-b432-4a1f-9a3c-9d64df130a61&DisplayLang=en