I dont have one, currently all of the IM clients are shit, i only use them because the minority does.
i REALLY HATE TO SAY THIS but for chat rooms and instant mess is hard to beat AOL . i cant afford AOL since my extreme DSL is allready near $50.00 even tho i had them both for a while. theres nothing more crazy than AOL chat rooms. MSN have a room chaparrone and curse words filter . the political rooms on aol are the best. you wont belief whats goes on in the gay room, but im not going to shell out a extra $23.95 but i miss it a lot.
AOL have both instant and chat rooms. also WINMX wish really sucks for down load mp3 got a really sicky bunch of chatroom "but a lot of them" almost worth getting WINMX just for the chat room. winmx is free.
WinMX is the only chat room i have been inside, i didnt last 30 seconds with all of the immature kids spamming everywhere.