Centericq is by far my favorite client. It supports just about everything (MSN, AIM, IRC etc) and it is really stable on *nix platforms. I think there is even a Win 32 binary around now, it is command line based so there's no images etc.
But if you're a bit of a command line warrior then it's worth a look.
http://konst.org.ua/centericq/
Cheers.