What the title says. I tried Ircle for all of an hour before the incessant beeping with every join/part gave me a nervous twitch. Oh, and it's unreadable, too.

X-Chat Aqua or Colloquy.

trying xchat Aqua 0.x now... isn't that like, an alpha build?
still, not bad.

I had Pidgin for a brief moment on my xandros box i think it would be worth trying out for teh mac :)

http://www.pidgin.im/

If you feel like shelling out 20 bucks, Linkinus is supposed to be really nice.

Although it does look awesome, it has problems with colour formatting, so #vrelay always looks screwed up.

I find that people that use Colloquy spend a large amount of time whining and bitching about it, so I'd go with X-Chat Aqua.

If you want 'Pidgin' for OSX, you'll want Adium.

I prefer X-Chat Aqua over Colloquy (having tried to use the latter, and failed miserably). But if you want mac-ish GUI, Colloquy is the way to go. I think Niki wuvs it.

I use Colloquy, and i have no complaints. But I also know nothing about IRC, i set it up and left it alone.

I use colloquy, I have also used xchat (on OSX, Win, AND linux), also used irssiX, MacIrssi, standard irssi (text-mode), ircii-EPIC4(and5), bitchx.

a bit OT, but gives my irc credentials: I've also used mIRC, pIRCh(was an awesome client when it was still being actively developed) along with several windows irc clients...

If you don't mind the console (Terminal, or get a real console app like iTerm) irssi is the way to go. MacIrssi is pretty decent, but if you're going GUI, might as well get a real gui app like Colloquy. You can set it up pretty much however you like, the default config left a bit to be desired, but after fiddling with it for a bit, I got it set up just how I want.

X-Chat is fine as well, just didn't feel quite polished enough to be a OSX gui app. I mean.. if I'm gonna use the OSX gui, I want the apps I use to FEEL like an OSX app, not just run on and look like a crappy little Xwindows box with text..

there's something called "Conversation" which is pretty and somewhat easy to use.