Question: I'm looking mainly at things like new SQL syntax, new kinds of locking, new capabilities etc. Not so much in the surrounding services like data warehousing and reports...

Answer: 
Filestream blob storage is the biggest bonus to me
[white paper on SQL Server 2008](http://download.microsoft.com/download/6/9/d/69d1fea7-5b42-437a-b3ba-a4ad13e34ef6/SQL2008_ProductOverview.docx)

This should cover most of the new features. I noticed the new date time data types and new security features.