I use Trillian instead of running AIM/MSN/Yahoo all at once - The new version is quite nice
Same here. It seems I don't need anything but IRC and AIM though. Barely anyone contacts me on MSN, no one on Yahoo, and my ICQ account is just there to say I have one.
I stopped using MSN years ago when it would go down daily for hours on end. It was a nice simple client though, unlike AIM which is a bloated POS. I compromise by using Trillian given I use both AIM and Yahoo and can use MSN in the future if it doesn't suck now.
I use AIM with Aimutation. I also use Windows Messenger when I am at work via its SIP protocol. I am not sure if Trillian supports SIP protocol but maybe ill check into it.