At home only!
I IM at home only.
I chat with my buddy who only lives 3 miles away.
We could use skype, yahoo voice, Xbox Live, Phone IM's - or GASP a phone!
I stay away from "chat" groups and strangers. (That's how I met my wife. I don't need any temptations.
).
I mainly use Trillian (AIM, Yahoo, etc all in one program).
I have my "do not accept" IM's from stangers and "always" ask for files.