Nettalk is a free and open source IRC Client for Windows. It is a fully-fledged IRC client with UTF-8 and DCC file transfer support.
Ranked in these QuestionsQuestion Ranking
Pro Easy interface
Simple and good looking interface.
Pro Can overlay incoming messages
Nettalk can be set up to overlay incoming messages. Especially useful for games.
Pro Encryption support
Pro Multi-lingual interface
Nettalk is available in English, Spanish, Dutch, Russian, Chinese, Hungarian and German.
Pro Built-in spellcheck
Pro Functionality can be extended via plugins
Pro Free and open source
Con No longer developed
Development ceased some time ago (2012).
Con Poor log management
It stores all logs in one file in a custom format.
Con German language
Is primarily a German language client, so the spell check, etc. is in German.