Limechat

While LimeChat is a nice & free IRC client on a Mac, it still has (had?) quite a few rough edges the last time i've used it.

I've since switched to Textual, which has its foundation in Limechat (it's a fork of it) that has since expanded quite nicely - both feature-wise as well as UX-wise.

Buying Textual costs 5$ but if you're cheap and can compile stuff yourself with Xcode, you can do so.

I'm in no way affiliated with Textual, just a happy customer...

If you type "open the wire door" in the chat, it opens a secret window with Limewire running in it.