Thanks for the input thus far. That's kind of disheartening about biking year-round being so tough. As for using the CDTA, I could very easily shorten the ride to 5 mi without an issue. Otherwise, I could also probably use the northway express service if need be.

As for having more then one bike, I currently have a Dahon folder (a 2-3 year old Vitesse I got used) that I've managed fine with over the winter in Boston. If I needed to use the CDTA, I imagine that'd be a good option.

So, assuming I used some combination public transit/folder over the winter, could you guys give some advice on a good commuter for the rest of the year. Keep in mind, I'd still want to be able to use this guy when it's raining out and whatnot.

What I've found that seem like good fits are:
- Bianchi Volpe
- Jamis Aurora
- Surly Crosscheck
- Civia Kingfield

Any additional advice? I'd definitely be interested in getting a good used bike, if I can.