This is largely a response to a thread on an email list regarding IRC clients. I thought I’d make a list of what I use now, what I’ve used in the past, and what is actually out there.

• mIRC - the first thing I ever used, and what I know a lot of people still use. It’s user friendly, but quite fast and light. Windows only.
• Trillian - an IM client that also does IRC. I’ve not used this for many years though. Windows only.
• Quassel - developed for Linux (KDE4 in particular), but now available for Windows, Mac OS X and several flavours of Linux. I alpha-tested this last year and it’s actually really good for monitoring several channels (on different servers if required) at once.
• Colloquy - Mac OS X only client that looks pretty, but that didn’t seem that instinctive for my needs.
• Empathy - Linux only chat client that also does IRC. It’s what I use most of the time, and it seems quite fast without getting in my way.
• Pidgin - does pretty much what Empathy does, but is also available for Windows and Mac OS X. It’s all a matter of choice really.
• irssi - text based Linux/Windows client that is lightning fast and great on old computers. It also forces you to learn all the commands. It’s what I use when I’m not using Empathy.
• Xchat - Another Linux client that has been around ages and that works exactly like mIRC so is great for switchers. I believe it is now available for Windows although I’ve not tried it.
• Konversation - KDE3 (and now 4 it seems) client for Linux. I used it once around 5 years ago so I’ll say no more than that.
• Chatzilla - Firefox/Sea Monkey extension. It’s basic, but useable.

There are lots more, but the above list is all the ones I’ve actually used.