I use irssi on my server, and connect to the irssi proxy from Colloquy:
http://colloquy.info/ on my Macs. I find irssi to be an excellent Linux client, and if I had to use Windows I'd probably use it there, too.
Foundation, if all you want to do with macros is expand some simple commands, you don't need perl to do that. There should be an irssi config file (~/.irssi/config on Linux), and about halfway down that there should be an aliases section. There's reasonably useful documentation on how to format aliases here:
http://irssi.org/documentation/settings#a_b, but the really simple stuff is like
explode = "me explodes into a cloud of glittering dust";
ferret = "me whistles, and a dozen ferrets frolic out and start bouncing all around and on *";
herring = "me slaps $0 around a bit with seven kippered herring";