Good IRC client?

I was looking for a new IRC client since I stopped using Chatzilla because Firefox freezes my laptop for some reason. Any particularly good ones? Reasons why it's good, if possible.

mIRC.
Relatively user friendly - downloadable.

Mibbit.
Really simple, images appear as small thumbnails to avoid clicking on things that are.....unwanted - browser-based.

mIRC's shareware, but there's no real "expiration", you can keep using it if you don't mind the nag dialogs.

mibbit's acceptable but is highly discouraged, as the network will only see mibbit's IP and not yours, which means only 3 people can use it at a time on the network. Same rule applies to any other mibbit-like service.

The two clients I would recommend for Windows: ChatZilla (for Firefox users, basically an IRC client within the browser), and XChat2 for Windows, which is a nice, clean, extensible IRC client.

mIRC's shareware, but there's no real "expiration", you can keep using it if you don't mind the nag dialogs.

mibbit's acceptable but is highly discouraged, as the network will only see mibbit's IP and not yours, which means only 3 people can use it at a time on the network. Same rule applies to any other mibbit-like service.

The two clients I would recommend for Windows: ChatZilla (for Firefox users, basically an IRC client within the browser), and XChat2 for Windows, which is a nice, clean, extensible IRC client.

-Points to the TS-
Doesn't want Chatzilla. O.o

Use Pidgin. Has an integrated IRC function.