I made the mistake of giving in and installing Live Messenger at work today. I've had to re-arrange my contacts 5 times today, because live messenger keeps taking contacts out of the groups I have them in, and re-ordering them. It's not just when I log in, it does it at random points during the day. Sometimes it empties entire contact groups, sometimes it moves the odd contact.
Add to that Pouya discovering a buffer overflow that crashes everyone on your contact list, and I'm glad I've got an old installer for MSN 7.5.
So bye bye Live messenger. I tried it months ago and it was slow and ugly. Now it's slow, ugly, buggy, and crashes. I am not installing Live Messenger. Period. If they change the protocol again, I'm going to use gaim or something else.