I must admit: I have been using Gaim for monthes. I do not say I like it but it was working at least. It has an ugly interface, bad user management etc. But I did not know any alternatives because everybody beleives it is the one and only.
Well not anymore. Since the new protocol is forced at MSN I had to reinstall Gaim. Did not work to well and it was very complicated with the dependency hell it needed.
So I downloaded Kopete. I am very amazed how nice handy, fast, easy to use it is. It has very good user management, beatufuly interface (with anti-aliased fonts) . And it was running the new MSN protocol without the need to fight for some external SSL library. Such things that you can merge user accounts to one and you can rename any of your partner make the life much nicer.
I recommend it to everybody, it is reaaallllyyyy awesome. The only problem: it takes about half an hour to compile it (dunno why).

yup, it's really nice for KDE users but it's still somewhat buggy for me (crashes on every regular quit). I use it on my main PC because I use KDE on it. My laptop however doesn't have that much power and I run XFCE4 on it (and actually considered to use it on my main comp, but I'll wait for v4.2 ).

I don't like running KDE applications outside of KDE because generally those run slower than the GtK+ counterparts such as Gaim.

As for the current I remain with gaim on XFCE and kopete on KDE. I don't mind missing MSN at the moment. But I like the fact that the kopete team wants an application that fits to the standard GUI and is not a ressource hungry skinned program.

BTW: The link to http://kopete.kde.org and will be released together with KDE 3.2