Microsoft have just released the beta version of Windows Live Messenger 8.1 to the general public.
It's got a couple of key news features my favourite being roaming profiles, this is something that has bugged me a lot recently with re-installing Windows every few weeks with new Vista builds - I'd have to get my yeti picture back out and put him as my display image. Now however it, along with your personal message is being stored server-side like my contact list, so it won't matter where I sign-in from in the future my stuff will just be there.
There have been a few tweaks here and there, couple of new features and the menus have been re-organised a bit too.
You can check out the WLM team blog here, and download the beta here.