I am so digging the new new Windows Live Sign-in Assistant. If you haven't seen it, it provides easy signin for people w/ multiple Passports Windows Live IDs. I use Windows Live Custom Domains to manage my devhawk.net email (which also rocks) which means I have my personal hotmail ID as well as my devhawk email ID. With the sign-in assistant, I get a slick login UI that lets me log in with either ID with a single click. Very nice. So far, the new sign-in only seems to be enabled for Windows Live Ideas, but I assume that will expand over time.
BTW, if you want this new sign-in experience, it looks like you need the new beta of Windows Live Messenger. There's a bunch of other new stuff in the latest beta - new features, better perf and a more polished experience. AFAIK, you still need to be invited to join the beta. I have a bunch of invites - if you want one, drop me a line.