I am using VS Team System 2008 version 9.0.21022.8 RTM, .NET Framework 3.5 SP1.
I get C# and VB.NET Intellisense, but not for F# May 2009 CTP.
UPDATE July 7th, 2009
I am installing VS 2008 SP1, maybe it is better than reinstalling VS 2008 from scratch.