I have ICQ for quite some time, but I'm planning to use MSN soon as well. Still, I prefer ICQ. I do know MSN, so I am able to compare them. 
The only nasty thing about ICQ is, your contact list isn't saved somewhere on their server, unlike MSN. But the good thing about ICQ is you can order your contact list very neatly. Also, there's the possibility to send SMS messages easy and free! Plus the fact that it can act as an email notification program. MSN only supports Hotmail (just another Microsoft conspiracy) notification.
And there are many many many options for the lay-out and the use of ICQ, but these can always be ignored. It's easy to use, but advanced users have their fun as well...
Edit: I've added AOL and Yahoo! to the list as well, but I wonder if there's anyone who will choose one of those as best chat program.
It's just there for completion...

The only nasty thing about ICQ is, your contact list isn't saved somewhere on their server, unlike MSN. But the good thing about ICQ is you can order your contact list very neatly. Also, there's the possibility to send SMS messages easy and free! Plus the fact that it can act as an email notification program. MSN only supports Hotmail (just another Microsoft conspiracy) notification.
And there are many many many options for the lay-out and the use of ICQ, but these can always be ignored. It's easy to use, but advanced users have their fun as well...
Edit: I've added AOL and Yahoo! to the list as well, but I wonder if there's anyone who will choose one of those as best chat program.
