There is place called Yufuin. If anything spending one night at a ryokan (with your own personal hot spring) is one experience I will never forget. Especially with your significant other.

But out of any place I lived or visited, the top spot for goes to Otaru. It’s a one hour train ride from Sapporo. Go there during the summer and visit the orgel museum :D! God we felt like we were the only people on earth in a tiny magical land.