MSn, icq, yahoo - MSN being my favorite. I use ICQ for file sending mainly. I use yahoo because people at work do for some reason and MSN is my favorite. I have used trillian but it doesn't allow use of emoticons (yes it has a big list but they don't really work unless the other person is on trillian - and even if they are MSN's emoticons are way cooler!). Plus, the reason I like MSN is because it's so damn simple and small; trillian is cool but in order to do so much it makes me feel like it's cluttered (much like ICQ)!