There are some really great entries appearing on the SQL Server 2005 Best Practices website. I just noticed this web page which discusses, amongs other things, some new features in SP2 like the vardecimal storage format and LOGON triggers. Take a look:
Top 10 Hidden Gems in SQL Server 2005 http://www.microsoft.com/technet/prodtechnol/sql/bestpractice/gems-top-10.mspx.
I also like the SQL Server 2005 Script Repository http://www.microsoft.com/technet/scriptcenter/scripts/sql/sql2005/default.mspx?mfr=true which provides links to some really useful scripts.