Suggestions on hokkaido itinerary in January

I am flying into Chitose on 7th arriving late morning and leaving on 12th in the morning. So far I definitely plan to stay in Sapporo for two nights so I can ski at Sapporo Teine on one day and do a day trip to Otaru on another. For the other 3 days I am stumped about which direction to travel outwards from Sapporo whether it be to Noboribetsu or towards Furano. I plan to take the train but am leaving the option of car rental open. Any suggestions on whether Noboribetsu or Furano is more worth it in Winter? Cheers.

I had a great time in Biei in January 2 years ago and can very much recommend it for great landscapes: http://monochrome.me.uk/blog/?s=biei

If you can't take bad smells, avoid Noboribetsu.Noboribetsu is full of sulphur smell. It's good side is that you can warm yourself up with onsen.
On the other side, Furano is either skiing or nothing to do.
Both have advantages & disadvantages.
I can recommend drift ice at Abashiri too.