My 10 cents:
TFS2005 was a joke - hard to install and even harder to maintain
TFS2008 was stable - easier to installer, simpler maintenance, and automated builds that work.
TFS2010 is EPIC! - installation is dog eassssyyy. Management is very easy; it's all a nicely laid out UI. Integrating it with VS2008 isn't so easy since you can't create projects in vs2008 you have to use vs2010 (which is stupid). TFS2010 also allows you to change the sharepoint project location instead of having those awful subfolders of TFS2008. TFS2010 also has tools like a burndown chart that is really useful for project management. It's like TFS2010 is for the whole production team including the clients! It still costs way too much though :(
