So, everything was fine. Turned off computer. Turned it back on after a couple of hours and my fonts look like this everywhere in the GUI now, not just in the xchat window:
http://img340.imageshack.us/img340/6361/wtf2gi4.jpg
Notice the weird colour of the text... it's darker then lighter and so on.
I have no idea what could've caused this and haven't seen anything like it