I am doing a session with a colleague this evening - Mike is doing CLR and I am covering TSQL enhancements. A question we will undoubtedly be asked is  "When do you use which?" As luck would have it - I just came across a rather fine article on this area and would recommend it to others http://msdn.microsoft.com/SQL/default.aspx?pull=/library/en-us/dnsql90/html/sqlclrguidance.asp