1) 7
2) Probably only around 4-5 hours a week currently.
3) I only have a few original titles, but I guess Monster Hunter 3 Ultimate is my favorite so far. I've never played the Wii version, so it's new to me!
Opinion: I bought one off eBay last year, after the Christmas rush ended, and it already seemed pretty clear that its supply was exceeding demand, so I was able to get it for significantly cheaper. I mostly bought it for the promise of new games in the franchises I like, but it was also an excuse to give my old Wii to my parents, since the family system just crapped out around that time.
So....with the exception of Nintendoland and Monster Hunter 3 Ultimate, the only things I've been using it for are my Wii backlog (still working on Xenoblade Chronicles) and some cool retro games on the eShop. It works as a Netflix hub too, which I really like. Oh, and it's not a system seller, but I love how the Gamepad works as a TV remote. Pretty handy if I can't find the actual remote.
All in all, I like the hardware, I just haven't got a chance to play a lot of the new games. Most of my gaming time has been spent on the 3DS lately. Oddly enough, my first year with the 3DS was almost identical to my first year with the Wii U. Bought it cheaper off eBay, and mostly played DS and retro games while waiting for better software. I really love my 3DS now, so I look forward to seeing what the Wii U will bring me a year from now.