Yeah, I use weechat.

But in the interest of sharing something new: I do also like ii, which is a minimal filesystem-based IRC client. To tail a channel's messages, for example, you could do

tail -f #vim/out

Then to send a message,

echo 'Hello, world!' > #vim/in

Fun for the first five minutes just pulling together a makeshift IRC client with tmux panes and the above, but then you realize the depth of the iceberg with its scriptability with standard Unix pipelines. Tail out into a perl script that pipes back into in for example and you have a bot.