I’ve been using Miranda at work for a while, and I’ve just now gotten switched over to it at home (from Trillian). I don’t do anything fancy with my IM programs, just chat, so Miranda is the best client I’ve found so far. It was originally an ICQ client, but it has been converted to support any protocol that a plugin can be written for. It supports the basic TOC protocol of AIM, which is all I need. They are working on the full OSCAR protocol which supports file transfers and such, but AOL has made it quite clear that OSCAR is their proprietary format, and they don’t want others using it (occasionally Trillian and other clients get into little band and forth break/fix coding wars with AOL). There are plugins for Jabber and MSN protocols, and many other “utility” plugins that do everything from get RSS news feeds to checking game server statuses. If you prefer a small simple IM client over a fancy bloated program, give Miranda a look.