Miranda Im - Most useful Instant Messaging Client

Since Version 0.5 it got really usefull, especially if you need a multiprotocoll client.

Get it here:
http://www.miranda-im.org/

Nice Icon set:
nova

Recommended Addons:
History++

Simply extract the icons into the Icons subfolder of Miranda (including the nova folder) and pick the new icons in Miranda via Options -> Contact List -> Icons