I mentioned earlier that I'm a big fan of the AOLYellowPages bot, as I find it much easier to get address data over I'M than by using a browser.
My new favorite bot is SmarterChild - it's a kind of general purpose bot. One feature I really like is the spell checking. Just type:
And the bot will give you suggested spellings. Spell the word right and you can get a definition.
Again, a useful UI that seems much more efficient than a browser.
Remember, to use these bots just add them as buddies to your AIM list and send them a message saying hello.