I use ICQ but only because most everyone else still does but I use Skype more and more these days. I hate how long ICQ takes to load and all of their stupid ads and endless russian spam. Skype works better for the most part but I don't like the interface.
By the way if anyone wants to try our Skype alternative, please do!
http://www.2much.net/miricam/
It doesn't have all the features that skype and icq have but then again its a work in progress, and its completely free to use. Enjoy!