Thanks, these are all good points.
I guess it shows by my post - I am a long time roadie, short time commuter. So, for me, it seemed natural to go for a road bike when taking up commuting. The roads around here aren't too bad, and I'm comfortable with the position. But I can understand where many would want a more rugged, upright bike.

Too bad the marketplace is relatively bereft of low-priced, commuter-type road bikes. Jamis makes some nice ones, but it seems like they're the only game in town.

I'm thinking of using my MTB for commuting when it gets snowy. I'm sort of dreading it, but if everyone else here does fine on an MTB I guess I will too.