User1759999623 posted
First of all, to possibly make this easier, you run both 2008 and 2010 side-by-side without any issues.
As for what to remove, just remove the Microsoft Visual C# 2008 Express and Microsoft Visual Web Developer 2008. Anything directly tied to either of these installations will be uninstalled at the same time.
After uninstalling and rebooting, go back through your installations again and remove anything that you don't want that is associated with VS 2008. If you're not sure, then leave it as it will likely not interfere with your VS 2010 installations
anyway.
Note, VS 2010 can be used with .NET Frameworks 2.0, 3.0, 3.5, and 4.0, so don't remove your .NET Frameworks.