I used Eclipse at my first job (Java) and liked it a lot, for OO programming it has lots of really useful features like generating method stubs and stuff like that.
Using C/C++ now I use Visual Studio with the
Visual Assist addon (which basically does the reference tagging well named refers to above)...it's not perfect, but I'm not sure what else is better. Lots of other people at work use SlickEdit, but I've tried getting into it a couple times and usually give up because its symbol coloring options aren't as deep as Visual Studio + VAssist and I've gotten accustomed to seeing just about everything (variables, enum values, function names, type names) in different colors.