I have just come out of a session at MEC2002, I'm here thanks to MSD2D and although the speaker Brian Murphy had to be very vague, because the beta is not out untill the new year. He did confirm the following which most people already knew:

STS and SPS will be fully integrated, with SPS using SQL server as it's backend.
Categories will be called Topics and be moderatable by specific users and generally easier to manage.
More drag-and-drop for Web Parts for users (ie Personalisation) from a Library of parts the admin provides.
More scalable, with Biztalk integration to make it work at an enterprise level (I don't know much about Biztalk so I don't know how this'd work).
Better modular backup/restore, but with reliance on 3rd parties.
Roles will be extendable, better integration with Active Directory/NT user accounts, so you can know who is online now etc and using the system.
.NET and VB studio integration.
Better reporting features.
Extended DDSC: web parts can communicate better.

All this is just my interpretation of what was said/intimated, so don't trust it too much! Also if anyone is here, look out for the guy on crutches hopping about, come over and say hello.