When I started developing in C in Vim there are two things I've gotten used to that I can't live without now: ctags and auto-complete (they help with eachother).
Ctags is great, especially for navigating someone else's code. What does this function do? Just ctrl-] and suddenly I'm at its definition. Something in there I don't recognize, same thing. Ctrl-t to go back up the tag stack. Ive become so used to navigating my code this way I have trouble without it.
Completion is just the way that Vim will give you completion matches in insert mode if you hit ctrl-n or ctrl-p. With C it's very smart about it and will automatically search included files. It's great for not having to worry about exact spellings on things. If you really like this sort of stuff there are a few plugins that do Textmate-like snippets.
If you like CTags give CScope a try. It's sort of like CTags on steriods. Also Vim can work with a combination of both (it loads both cTAGS and cscope.in) so you don't loose any functionality.
The biggest plus you get when using CScope is the ability to do a "reference" search. You can find all references to a given symbol in your project quickly and easily which I find invaluable for refactoring (what's going to be affected when I change this?).
Ctags is just as accurate at scanning C declarations as an IDE, and with a bit of vim magic, it even auto-updates when you save files.
One thing to realize is that vim IS an IDE of sorts. Only, it's far more extensible for the same effort. (although, from my brief forays with emacs, emacs certainly beats vim for extensibility)
Emacs also supports ctags. I didn't find it very useful with C++ though, which is my usual language, since it didn't autocomplete member functions - I think it's supposed to work, though I couldn't be pushed to tweak it.
Cscope, as commented on the article's website, sounds quite interesting too.
What about conditionally compiled code, based on preprocessor definitions? And what happens when you change one of those definitions in the editor? Visual Studio, for example, will re-scan the source in the background.
And what about tokens created using the token pasting operator ## from include files that are included multiple times (e.g. code generation hackery)? Visual Studio will at least locate the include file which introduced the token, and of course will be able to complete on the token, aware of its type etc.
Ctags is great, especially for navigating someone else's code. What does this function do? Just ctrl-] and suddenly I'm at its definition. Something in there I don't recognize, same thing. Ctrl-t to go back up the tag stack. Ive become so used to navigating my code this way I have trouble without it.
Completion is just the way that Vim will give you completion matches in insert mode if you hit ctrl-n or ctrl-p. With C it's very smart about it and will automatically search included files. It's great for not having to worry about exact spellings on things. If you really like this sort of stuff there are a few plugins that do Textmate-like snippets.