Windows Live now integrates Facebook, You can login to your Facebook account, along with MSN account. That means you can chat with your Facebook buddies right on MSN messenger. No more small windows with blinking text on browser for new message notification. You will be notified via msn messenger.
You can also read wall posts and updates on MSN today screen, but it comes up pretty big and disorganized making it even harder to browse. Chat has been made simpler and i love it.
(If you are using windows vista, some updates may be required if you haven't installed sp2 and windows 7 interface, the installation wizard will guide you through on that)