Surface Pro 2, used to do a lot of my art on paper then move it to my desktop with my Cintiq 12WX. Got the SP2, stopped buggering around with paper, do all my art on the device. Lot less issues with storing supplies and old books for one, let's me do art anywhere. It's been helping with my business too...since I'm the artist there, amongst other things.
Also it plays lots of games so productivity be damned, Sonic Generations, Skyrim anywhere I go. :|
Thing is I only found out about it while my brother was buying an office chair, saw it, played with it and went review crazy till I caved and got it. So, hooray random chance I guess.