till now yahoo got 13 votes then msn with 12, lets see after some more votes who's most members' favourite
I haven't voted yet because you've left out GTalk But looking at the choices, Yahoo! would be mine as well.
My personal choice is Trillian, I mainly use AIM+MSN with Trillian, not much of anything else on it though at the moment.
only thing yahoo is good for is the radio, i prefer msn, webcam works better on there too, easier file xfer ..etc.
There are so many messengers u guys are telling that I don't know... are some of these provided by your ISP?