Not every organization will be able to reap benefits by moving to 2008 however, if you have the chance you should go. The one thing I will state emphatically is that if you are thinking of going to 2005 from 2000, don't bother. Make the leap.

Aside from the things Steve mentioned, SSMS has had some improvements which are pretty cool as well like Intellisense and the display of missing indexes when looking at execution plans (only able to be viewed when you looked at the often confusing XML plans in 2005). I will probably post about some of these features in my blog in the next couple of days when I get time to breathe.