Pidgin has come a long way since I first took a look at it a year or so ago! I was reminded the other day about it and took another updated look – w0w, that’s a lot of chat clients: Pidgin is compatible with the following chat networks out of the box: AIM, ICQ, Google Talk, Jabber/XMPP, MSN Messenger, Yahoo!, Bonjour, Gadu-Gadu, IRC, Novell GroupWise Messenger, QQ, Lotus Sametime, SILC, SIMPLE, MXit, MySpaceIM, and Zephyr. It can support many more with plugins.
Available for nearly every major OS, Pidgin is looking mighty fine. Is there any other chat clients you guys are using recently?