Gtalk

[gamefreak]

http://talk.google.com

Need a Gmail account to use.

[CokeCola]

Well, I like it. The interface is clean and the windows are small. It's not as fully featured as a lot of things, but it's still taking up 13 MB in RAM.

Pros
-Looks good and small
-Integration with Gmail
-Useful notifications. When you receive a new message, a notification with the message text briefly pops up.
-Great voice chat. Way beyond AIM.

Cons
-Ignores Windows Themes. If you've got a customized look, it's out of place.
-No Transparency effects (I like IMs and Contact Lists to ghost when I mouse away).
-No group chat.
-No group voice.
-I don't think it has permanent logging.
-No Tabs. The windows can all be rolled up, and they snap together vertically, but it doesn't really function like tabs. Close, though.
---Google or not, nobody will use it. Messengers are judged by who's on them, and all of my asshole friends say "I'll switch when everyone else starts using it." I hate AIM, and we'll never get away from it unless a powerhouse like Google makes a client that supports their propriety system and AOL's to work through the transition.

[irrossistable]

Uh, I've had Jabber for awhile...

And for confirmation, there is in fact is no permanent logging.