Adium

I recently installed Adium to check out how good it is, and so far I'm impressed, it is a hell of a lot better than Messenger:Mac from Microshit Microsoft.

My favorite feature is the ability to change the colors on the contact list and make it transparent, now I always keeps my contact list open.

There are many more features i like about it, such as changing sounds and message window styling, Check out the Adium website for screenshots and to download it.