Here is lot's of info about new stuff coming:
http://www.microsoft.com/whdc/winhec/Pres05.mspx. Maybe not all of it will come with Longhorn, I don't know
Driver DevCon'05 presentations aren't public, so that's where it seems like most of the cool stuff were discussed (I wasn't there, so I just assume that ).
I don't see why everybody assumes that Longhorn will only be about Avalon and Indigo. They're just frameworks to build stuff easier. But it is still possible to create cool stuff without them. Shell looks nice, btw: