You raise a good point -- when I was writing reasonably small programs, it was gvim all the way for me. However, the minute you have to interface with a library

You raise a good point -- when I was writing reasonably small programs, it was gvim all the way for me. However, the minute you have to interface with a library like wxWidgets, for example, the IDE really shines through with auto-completion. To answer previous posters, it just replaces an alt-tab to firefox and a couple of API lookups, and saves you about 5 seconds per obscure, unfamiliar API call.