I'm a work-at-home non-commuter (ha!), but I try to ride as much as I can for errands and such. I recently had my LBS build me a mountain bike. I was really happy with the bike, and then after some reading it looked like people recommend road tires instead of knobby tires - because I'm not actually taking the goddamn thing into rough terrain.
And I'm sold! The ride is so much smoother!
Just wanted to share a bit of the happiness :)