Win: Digsby Mac: Adium And both kick the crap out of Pidgin as of the last time I tried it. Digsby goes well beyond the typical IM client by also tying into Facebook chat, Twitter, POP/IMAP mail notifications and every client in the intertubes, and data syncing between computers (you have a generic Digsby login that handles everything, makes migration and going between boxes easier than trivial), but unfortunately is Windows-only. Mac and Linux support are planned though. Can't wait - it should take over a ton of the extra cruft I have.
I use Pidgin, and Gaim before that for several years. I stumbled across Gaim the first time I tried out Linux, many years ago, and found it to be much more pleasant than whatever version of the official AIM client was current at the time. As soon as I realized Gaim was cross-platform, I switched. However, I'm extremely stubborn and resistant to change, so once I had started using it, I was hooked (that I switched so readily to begin with is a testament to how terrible the official client was (is?)). Since then, I've tried a few other systems very briefly, and found a reason to dislike all of them. AIM is still terrible. DeadAIM is like a Band-Aid on AIM; it hurts less than the original wound but you'd still rather avoid the issue altogether. Trillian makes my eyes bleed (if you're looking for more visual options, this one actually has potential). Maybe if I cared about audio and video support, I'd see things differently. To be honest, though, I've got a chat client so I can type things which friends will then see. Occasionally I send a file. I have a soft spot for programs like Pidgin, Foobar2000, and their kin, which do only one task but do it exceptionally well. I don't want anything shiny and obnoxious, I want a program that looks just like all my other programs, and lets me type things to other people. Pidgin does this brilliantly. As I said, if your needs tend towards a more glamorous client than Pidgin, you might want to check out Trillian. I can't stand it, but that might make it perfect for you.
Well i don't want any thing flashy, almost the complete opposite im using rainmeter on my secondary monitor, and i keep my buddy list docked on it as well, wanted something minimalist to match the rainmeter stuff. pidgin is great i've been using it for years. (gaim before like you mentioned) discovered it on windows tho, I'm yet to wonder in to linux.
ive got Pigdin & Miranda installed but i rarely use them on anything other than my usb stick (running portableapps on it) I run for the most part MSN with the crap hacked out of it no adds no browser shake when nudged no nudge protection no premium content, multi line sigs , character boost to like 5000, poligamy etc
I tired to use pidgin the otherday but I wasn't very impressed, always used MSN, I have no friends that use anything else so no need for mutiple logins.... I dunno just kind of fed up with stupid MSN adverts
Adium on Mac. Nothing can beat it, even if Digsby gets ported. On Windows, I use Miranda and a few plugins to customise it. Nice and minimalist. Edit: Angleus, try apatch
AdiumX and occasionally iChat Although honestly I wish apple would just put support for MSN into iChat Spoiler (yes I know you can do it via jabber-msn-proxy madness, and no it isn't good enough to bother with)
I've never actually used iChat, because I don't know anybody that isn't on MSN. I just got sick of using the MSN client, both on Mac and Windows. I may go back to it if they update the OSX client to allow signing in from multiple locations (like they have in the v9 beta)
Up until very recently Miranda. Ideally I'd still use it, as I love the minimalism and the customisability of it, however: It doesn't seem to like sending messages to off-line contacts, which is quite important to me now, so I've recently moved over to Pidgin. It's okay I spose (a damn site better than any of Microsoft's efforts), but it's a bit bloated and uncustomisable compared with Miranda. I'm hoping the next proper update of Miranda will fix the issues I have and I can switch back.
When i used it my app of choice was miranda, But i dont use it anymore, it was very rare if any of my contacts were online at the same time tbh. If i need to get hold of anyone i give them a ring or a text maybe even a email.