A combo I recently moved to – after using 5+ years irssi, 5+ years weechat – is the graphical client Textual[1] (OS X only) backed by znc. It's smart enough to do replaying backlog and similar for you.
I also really admire their licensing strategy. The entire project is open source; build it yourself or pay us to do it (then we'll throw in support as well)[2].