After using IRC via Mozilla then meeting some folks (like the XDoclet folks) who use Yahoo I thought it was time to try out a cross-IM-protocol client. I've tried gaim and vista which didn't quite cut it. I've been using Trillian now for an hour and I've gotta say its pretty slick.
Though a quick tip for any possible Trillian users. If you click on the 'hide' buttons (the green toolbar buttons in the default skin) and want to find your hidden windows, use the 'drawer' which you can expand by clicking on the dark area on the right hand side of the buddy list. This took me quite a while to figure out!
Many thanks to the posting by gerbig for helping me figure this out!