What's your favourite instant messenger to use?

for me it has to be MSN. I've tried ICQ and Yahoo Messenger before but both are not to be liking as much as compared to MSN. Plus, almost all my friends has an MSN account so its much easier.

I use skype on my pc, is very performant with my kubuntu OS... i'm very sotisfed by the high quality of the voice conversations

In my country the most popular instant messenger is Yahoo!. Everybody uses it, and I like it because all my friends are using it, and it's easy to use. you can even change the skins.

Actually I don't use any. LOL I prefer not to be bothered when I'm online.

My favorite is Skype, because it's stable, and the sound quality is better than all the others. Reason being, Skype is VoIP with IM, while the others are IM with VoIP. Skype doesn't have all the cutsie emoticons the others have, of course. I'm the only one in my circle of friends who touch-types. So of course none of my friends care as much for IM as I do. I was perfectly happy with Windows Messenger, because it was stable. It's supposed to have some VoIP capabilities, I believe, but we never did figure out how to enable them. A couple of my friends got me using MSN, which I believe is now Windows Live. It was nice, but it kept failing to locate server. During this time, we had been trying to get another of my friends in our conversations. He was using Yahoo!, and we soon switched over to his side. Yahoo! Messenger crashed incessantly. I'm a tech, and I treat my machines the way a dentist treats his/her own teeth. I won't stand for an unstable program on my machine. I removed it promptly, and went back to Windows Messenger. Then I came across Skype, a name that was strangely familiar to me. As it turns out, it was a program I'd used years prior to make free phone calls. I found it to be perfectly stable, rarely even dropping a call (usually only when I'm talking to my friend who has T-Mobile). It also had a much clearer sound. All my friends have switched over. Since then, I've found a package on the Internet that turns Skype into Portable Skype, so I can use it from my flashdrive. Skype is great. I've already been through one long-distance relationship on it, as in halfway across the world. It was actually a lot of fun. Of course, she had a better webcam than me. :P Unfortuately, it's been awhile. The relationship never ended officially; she moved to Iraq, and I never heard from her again. :(

I use icq,msn and skype.Icq is not as popular as it was.I sometimes check my offline messages in icq.I don't use it very much.My favourite ones are msn and skype.I have lots of friends registered in both of them.Msn is very popular worldwide and %90 of internet users have msn account.It's is easy to use and file sharing option is good as well.

ICQ was my favourite until AOL bought it out and screwed it up. Now I exclusively use MSN, but mainly because everybody else is on it. I honestly think it is 10 years behind its time, and I can't wait until gtalk is further developed.

I basically use AIM.. its pretty simple and my favorite because all my buddies are on it!