Never run under Wine what you can run natively. Winamp has superior native equivalents (xmms, amarok). Yahoo! messenger has a Linux version, or you can use gAIM or Kopete. There are far more IRC clients available for Linux than for Windows. RO (unfortunately, I used to play it) doesn't have a native equivalent. Wine will probably do it. Guild Wars is known to work
. No mention of Gunz. It might work, you'll just have to try it and see.
Ports of commercial Windows games can be found at tuxgames.com
. I personally run:
Corewars (geeky assembler programming challenge
), BZFlag (3D tank shooting game), Nexuiz (FPS), Return to Castle Wolfenstein (costs), Enemy Territory
(engine is closed-source), NetPanzer (multiplayer strategy), Neverball (very tricky 3D guide-the-ball type game), Freedroid (Paradroid clone), Enigma (2D puzzle), and Supertux. All native. I used to play Counterstrike as well, using Wine.