Nil was just talking about IM, and I've been thinking a lot about it lately, too, although in the last year I haven't done it much... at work I am too easily busted, and it's one of those things I get so distracted by- I mean hours and hours of fun, while nothing else gets done- that I usually log on as invisible.
Also, I only ever use the Yahoo messenger (this provides a lovely new mail notification service), and most everybody seems to use something else.
so I've just discovered this very interesting messaging device called "Trillian," by Cerulean Studios. Has anyone heard of it? Here's their little blurb: "Communicate with Flexibility and Style. Trillian is everything you need for instant messaging. Connect to ICQ, AOL Instant Messenger, MSN Messenger, Yahoo! Messenger and IRC in a single, sleek and slim interface."
I downloaded it very easily on my pc at work. Unfortunately they aren't ready for the Mac OS... as soon as they are, I'm there.