I'll be upgrading the office to it, mainly because it's a new file version (though everyone will be set to save-down to 07 file type) just in case someone sends us a 2010 type file.
Also mostly upgrading because one person is still on 07, three on 08, and I'm the only one using 09. I've finally gotten enough time to customize a partial CUI file to have a good couple Ribbon tabs for expediting and increasing use and ease of conforming to company standards and some tools to expedite detailing. Should be a good reason to get everyone to WANT to upgrade as well.
All that is nothing I couldn't accomplish with 09 though, so it's not really specific to 2010.
However, I have been wanting to mess with parametric blocks to see if I can come up with any applications where they'd work... but I think I may like to wait until the bugs are worked out to make sure no "surprises" come my way if I start using them.
Otherwise... nothing terribly impressive to me.