The best instant messaging application for Windows I've used to date and the only one besides Babuki (which I found clumsy and very hard to use in comparison) that supports Facebook IM.  Supports nearly every major IM service available.  Facebook, MySpace, e-mail integration & server-side contact list and settings also add much convenience to the experience.

This program saves me so much time!!  With multiple email and social networking accounts along with twitter, Digsby allows me to keep an eye on what's going on with all of them at one time and boasts an easy to navigate, intuitive user interface that makes it incredibly easy to use.  On the fun side, Digsby has an array of colorful skins and options to make it your own.  I have been very impressed with this program and have found it quite useful.  I will be using this quite regularly and recommending it to all of my friends!