I assume you have the latest version? If you don't, get the latest. May help with crashing... I've been using it for more than a year, and have had a few intermittent crashing.
Secondly, just delete the application or get an uninstaller like ZapIt so it can rid of the preference files, etc.
I have the latest version of Adium too, and it does crash. Maybe once every couple of weeks, but it is annoying. I would change to a different chat client, but I have a few thousand chat logs on Adium