I've used kvirc (found on freshmeat.net).  Has worked quite well for me (dcc
sends, receives, etc...).

> > What GUI IRC client is most popular right now? It has been a LONG time
> > since I have used IRC, and really don't care for BitchX. Thanks!
> 
> It seems like most people (myself included) use xchat (www.xchat.org).
> It is currently undergoing a major rewrite, but the stable versions
> should be fine (i.e. whatever comes with your distribution).
> 
> My only problem has been with DCC private messaging.  It used to work
> wonderfully (every private conversation was under a different tab), but
> for the past year or so I have had problems.  Not enough to get me to
> switch, but enough to annoy me.