Zeus IDE. Just found it on google and according to their site, it's language neutral, windows based, simple, lightweight and oh, 20 MB.
It would definitely be very convenient to have one that can compile several languages, but I didn't expect as much. Is there one? I am going to try some of the ones suggested here when I get a chance.
Synfig studio is truly bad. It doesn't even have an eraser tool and all those ugly windows are everywhere.
*edit* after more searching, it isn't just according to their site. Zeus IDE has built-in support for more than 20 programming languages (C++, C, D, Java, Ruby, Python, Lua etc.), includes syntax highlighting, can be configured for your language and is more than 5 times smaller than Visual C++ Express at just 20MB.