…for its bloody powerful simplicity that fits Unix philosophy and toolset very well and helps to achieve less and more complex tasks in very intuitive way.
Let’s say I need to find details of all test cases in GDAL autotest package referring to GetNoDataValue method of Band class from Python bindings:
$ cd autotest $ grep -l GetNoDataValue *.py | xargs gvim
All files answering the filter are loaded to Vim:
I’ve seen may questions on the Usenet what’s the best IDE for Unix, especially comparable to Visual Studion and in most cases nothing well-working came out. Means, there is no such IDE for Unix. My answer is: Unix, with its astronomical number of small tools, is a perfect IDE, so nobody intends to develop anything like that.

I’ve tried just about every editor out there and keep coming back to Vim. Since I use three platforms it gives me an editor that works everywhere I do. I’ve nothing against all the others, but even when I stray for a while to try the latest and greatest, ultimately Vim gets my vote.
If you’re a Vim user you should consider donating — it’s a charitable cause…
I have similar feeling. I use Vim, actually gVim, on Linux, Mac OS and Windows (together with mandatory GnuWin32 toolset). On windows, I heavily use Visual Studio too (with ViEmu add-in, certainly :-)), because in my opinion – yes, I’m a very fun of Open Source still – it is the best IDE available on the market, unfortunately. However, I’d wish to see KDevelop, Anjuta or Code::Blocks as good as this IDE and debugger GUI.
Vim + <list of scripts and plugins> + ctags + id-utils + grep + find + xfce-terminal + terminus font = mloskot’s IDE