We have been looking at VS2008 Beta 2 for some time now and finally we got the RTM in our hands. So, we have initiated the upgrade of our EPiServer CMS 5 code base to Visual Studio 2008/.NET 3.5 and it is looking very good, everything compiles and runs perfectly fine. I got a 95% pass on the unit tests, the failing ones are mostly environment related and some method on the Assert class that have been obsoleted. In the coming weeks our test team will do a full regression test on .NET Framework 3.5 for EPiServer CMS 5 SP1 to make sure we don't have any compatibility issues. And to be clear, we will not require you to upgrade to Visual Studio 2008 for SP1.  

For information to come in the next weeks..