Sapporo is awesome. Neisiko is awesome. I'm jealous. I wanna go back.
For Sapporo:
-Raemen Alley (best in all of Japan)
-Olympic Ski Jump or Moriwa (keep in mind visibility)
-Maruyama Park
-Beer Museum (FREE)
-Historical Village (if you have time; an awesome blend of Japanese and Western architecture).
PLUS, Onsen in Hokkaido; especially if its snowing. Just something awesome about it.
I plug this stuff like crazy but its relevant... I did a travel series on Sapporo which can be found
here. I'll be posting more later.