As I was moving away from the bloated world of GUI (as always), I came across Finch the other day. Finch is a console-based IM program that lets you sign on to AIM, Jabber, MSN, Yahoo!, MySpaceIM and other IM networks on a *nix box.
It's fast, sleek, friendly enough for a terminal junkie and based on libpurple.
The UI (ASCII UI?) is quite similar to that of Pidgin. Keyboard commands are quite obvious and easy.
Alt+W brings up a window list which is more of a "taskbar in a window" for Finch that is,
Alt+C closes the current window,
Alt+R resizes the active window,
Alt+M moves the active window,
Alt+A brings up an "Actions" menu using which you can open windows relating to a bunch of things,
F10 opens up a menu bar,
Ctrl+C/Alt+Q allows you to quit Finch (duh!),
and that's not the end of it. The manual page describes a few (okay, a lot) more shortcuts but the ones I mentioned are most frequently used by me.
Apart from that, it also has a nice set of plugins, my favorite being "psychic mode" and also Buddy Pounces to sneak up on unsuspecting victims (read Buddies).
Configuring the application can be done via the ~/.qntrc file using which you can change colors, key bindings, mouse configuration, menu texts and what-not. Haven't tried it personally but the man page says it can be done.
In short, it's basically Pidgin on a terminal. Cool? Definitely...