IMO, the coolest feature is the MSN Spaces integration. I could live without Winks, and Nudges are politely but firmly disabled, but the Spaces-driven contact cards and gleams are a great feature.
...And one night away from Newsgator and I'm behind the times. Dare mentions Messenger and also that MSN Spaces is now out of beta too, and Mike Torres covers some of the other new Spaces goodness. Yummy.