sic

With hundreds of IRC clients out there, it's sometimes hard to believe that a new one was needed. Here are the highlights of this software:

   + absolutely NO scripting ability.
   + termcap based (e.g. fast!).
   + emacs-style key bindings
   + compliant with RFC 2810, 2811 and 2812.
   + virtual windows à la screen(1).
   + multi server support.
   + non blocking TCP connections.
   + basic support for multi-homed systems.
   + IPv6 support (requires RFC2533 compliant API).
   + everything goes and stays in the lastlog.
   + convenient scrolling (with searching capabilities) in the lastlog.
   + 10 display filters! (2 ignore features based on this).
   + built-in counters to hide repeating messages.
   + highly customizable. (format strings, filters, reformating, ..)
   + customization possible at every level (channel, window, server..).
   + non blocking DNS lookups (A and PTR records).
   + convenient multi-server "tabkey" style completion (for /msg, /squery).
   + "space key" style completion (for public discussion).
   + DCC support.
   + CTCP support.

sic is still alpha, so you should expect alpha quality. However, it is quite stable and no longer crashes when something isn't implemented yet. For more info/details on the project, check out the SourceForge Project Page.