Much (too much maybe) has been said about Visual Studio 2005 already but if you’re working with Visual Studio 2003 for your daily living (like I am) you want 2005. For me, there’s one new addition that absolutely does it no matter what can be said about 2003: automatic renaming.
I tend to mess around with my class names renaming them from this to that to see whatever looks and feels best. With 2003 and editors you soon resort to some kind of Find/Replace command which tends to be somewhat error prone (for me at least). Visual Studio 2005 replaces your typenames automagically when you rename your class files. No more error prone search actions for me: I’ll just blame the IDE from now on.
Oh and Smalltalkers and Lispers: please realize I already know and love the languages you also love so much. I’ve witnessed their awesome powers and can get a little frustrated sometimes because I cannot make make my living using them (yet). The .NET framework is the best I can get at this shop for now…