I used to use Pidgin, but I grew very sick of all the problems with it. I then tried to switch to Windows Live Messenger, but I had several friends who refused to use anything but the AIM network, even though they all used a server-neutral product like Pidgin, so I had no choice but to keep Pidgin around for the majority of my contacts. Eventually, I became so sick of having to use it and so offended that people wouldn't add a Windows Live ID to their Pidgin IMs that I stopped talking to them and just used WLM. Since then, I've found Trillian, which is much nicer-looking than Pidgin and much better at what it does. It's more stable, and its feature set completely encloses Pidgin's as far as I can tell.
Right now, I'm using Kopete, which is Linux-only, but I have a Linux virtual machine I use for it and some other apps. It has a feature no other messenger has in that it displays buddy icons next to each group of messages by that person, instead of throwing it off in the corner or not using it at all. I very much like this because just like on forums, I have an easier time with icons than with names. Pidgin doesn't offer that. In fact, Pidgin doesn't seem to have any unique features, and even the core basics of IMing other people seems to be broken. Even having vowed to never touch the piece of garbage again, I still have friends that use it, and they keep missing my messages...
My recommendation is Kopete if you have Linux or are willing to use a VM, and Trillian otherwise. Pidgin is a piece of crap. I honestly think the only reason why it continues to exist is because it's open source and a lot of people are using it for only that reason. I briefly tried MirandaIM, but it only took about 20 minutes of being unable to get it to function at all until I realized it was useless.