So the key difference from a technical point of view is the 64 bit architecture and the seeming necessity for 8 GB of RAM. This means that presently I can't run VMs of it on any machine I own.
Let me take a chance to talk about 64 bit. Few people who promote it really understand what it does. I have seen a number of 64 bit architectures with 4 GB or RAM. Actually you can managed 4 GB of RAM as well, if not better with 32 bit. The entire difference between 64 bit and 32 bit is how much RAM they can manage. 32 bit can manage, in theory, 4 GB of RAM but places a limit of 4 GB.
So far all the VMs of SharePoint 2010 I have heard about need that 8 GB, so there is going to be a problem getting a look at it.
It is called "20" "10".
There is a great deal of talk around expanding Social Networking and using Silverlight. People are talking a great deal about good stuff coming in Social Networking, that SharePoint will be pushing in that area.