I've been riding an Electra Townie 7D around town for the past 5 years. Before that I had a Trek 730 mtn. bike for about 15 years. I'm looking to get faster on neighborhood streets and paved bike trails in town. And take on a 25- to 50-mile rails-to-trails paved path.

I prefer the upright position on a hybrid. My quandary is whether the "hybrid-mtn. bike" that's the Sunfire or the the "hybrid-road bike" that's the Absolute 3 would keep me happy long-term. Occasionally I might like to get on hard-packed dirt or gravel roads. Mainly I'll be on pavement.

Can fatter tires be put on the Absolute 3 when I wanted to get off pavement?

Any opinions or anyone have any experience with either or both of these bikes?