Behold! The Zealot Speaketh unto Thee
So it's about time I mentioned XChat
. This multiplatform irc client is free (yes even the windows version is free!), and supports many scripting languages: last time I counted it was seven but it seems guile has been added, so that makes eight
Now, if you want to "do instant messaging" as well, there is bitlbee
which works with every
irc client. It functions as a gateway between irc and IM. Bitlbee has been working reliably for over four years here.-ism
If you want a little minimalism I believe xchat+bitlbee make a very good combination: bitlbee has no gui at all; xchat's interface can be reduced to the bare chat necessities. I have attached an example screenshot of how it could look.
On the other hand, if you prefer all sorts of gui widgets and stuff, xchat can do that as well; I don't have a screenshot as proof though...