Ok, back in December I posted about how I started using a program called Pidgin [Re: Goodbye Trillian]. I've not looked back since, and only missed a few little things about Trillian (such as the amount of emoticons it supported).
However, Pidgin is quickly erasing any doubt that it is the best instant messaging client ever.
For instance: I got a add on for Pidgin that allows me to post Twitter updates. (Yes, I have Twitter - www.twitter.com/taddmencer). This is gold for someone trying to stake a claim in the Twitter-world. Or nest. Or whatever people would call it.
There are other additions to Pidgin such as the ability to use your xfire account to chat with online gamer friends. You obviously can't see detailed information such as what game server they're playing - but you can send a message to them.
There is also a plug for Facebook that I've not used (it uses a web proxy so if your office blocks Facebook you can't use it).
The plain fact is - there is a lot you can do to make Pidgin work for you. I also have two AIM accounts running - one for business and one for personal so anyone can get a hold of me when necessary.
Check out the available plug ins.
And then go download Pidgin - http://pidgin.im/download/