I use everything too much due to my love for the Metro UI, although I do enjoy gaming with Live achievements. I am excited about using my phone instead of it being just a product I carry around with me, looking forward to the updates coming soon.
I picked the Zune integration. Having this built in is what really kept me from getting android. Its hard to just stop at that one thing tho as i also love the UI and how fast the phone is. At work everybody else has a android phone and i was showing somebody a app today and the first thing he said was "That phone is fast....i hate android now"lol.