So after switching to Apple for most of my hardware (I grabbed a 12" G4 powerbook and a mac mini), I've been looking for a decent IM client. Back in the Windows world I used Trillian, but when coming to OS X, I couldn't find much. I played with Fire - it was missing a lot of stuff, but worked. I was then pointed in the direction of AdiumX. After importing the Trillian sounds from a windows machine, I found the usability to be very good. Needless to say, it's now my choice IM client for both the powerbook, and mac mini. If you're running OS X, and want an IM client, give Adium a go. You won't need much more.