Once you've narrowed the field to tires with wide tires (for bad pavement), reasonably low gearing (for bridges and approaches), plenteous attachment points (for racks and fenders), and reasonably stout frames (bad roads, again), you've cut out 3/4 of the bikes in the shops. Personally, I'd go for drop bars (for windy days) mounted high (for easy traffic checking around you), and cut out 2/3 of what's left.

Then it's time to head to the bike shops and start test riding whatever they have that fits the bill. You're going to spend a lot of time on the bike, so you want it to be comfortable and fun. Once you run into one of those, buy it, ride it, and don't look back. (At least for 2-3 years!)