I've just installed Visual Studio 2008 so that I can start evaluating it for potential (read as 'as soon as we're allowed') deployment across the development teams here.  The very first thing that I notice was understandable but still rather disapointing.

As you may have read, Visual Studio 2008 will allow you to work with different .Net Framework versions (namely 2.0, 3.0 and 3.5). 

This is great, sort of. 

What I noticed was that the Solution and Project files are not compatible between Visual Studio versions.  Whenever you open a Visual Studio 2005 Project/Solution, Visual Studio 2008 will ask you to convert it to the new format.  You actually code itself does not change.

This isn't really a massive problem, but it does kind of mean that if you want to do the upgrade then all of your team members will need to be using the same version of Visual Studio to be able to work on the same projects.