I see I'm coming late but I use xchat in Linux (I think pidgin kind of sucks in comparison but it's good enough for a casual session
).
I did not know it was not free on Windows (and I voted for it before I found out about it).
I think it's really cool and the feature mentioned by Hectate, as well as many others, is available in Xchat too (in Preferences->Plugins I think).
The unofficial build should be ok (good post, titi!
)but run an antivirus as well as a malware scanner on it before installing.