I'll throw my hat in the commuter bike ring, I used to ride my old stove pipe Schwinn with drop bars and while that worked, it wasn't very comfortable. I changed and old steelie MTB into a drop bar and that worked really well, but it was a bit on the small side. I liked it because I was a bit more upright even with drop bars.

Fast forward, I have a roadie and a MTB with discs. The roadie is my fair-weather, fun, I-wanna-go-fast bike that I commute on from time to time. The MTB is a base model Trek 3500 with mech discs, it handles well for what I need, I threw some fenders on it and my lights. I like the upright position since I ride with a backpack (hated a rack and bag when I tried it), plus the discs work flawless in the rain, and stop better IME.

The only things I don't like about the MTB is the fork, it is the base model spring tension fork. It will suit my purposes and I already had some studded winter tires for a 26" wheel, which is why I got it. Plus it is last years model and was on sale for a really great price, and since my old drop-bar converted MTB was too small, this fits perfect.

But if you don't want tires THAT big, a hybrid or cyclocross bike would be your best bet. My coworker got a Specialized cross bike at the highest option level last year and loves it. He tours on it, rides gravel and RTT paths and commutes almost every day on it. He sings it's praises anytime he can.