A number of good suggestions here! I faced a similar problem when I decided to start commuting in 2008. 40/21 didn't cut it for the 20+% hill just at the end of the ride. Even using the newspaper route up the hill was not an option and with cleats, walking was seriously not walking!
My solution was two steps. First I commuted on the RockHopper that did have plenty of low end and did that for a year. I was then in better shape and was actually able to make it up the hill on a 40/26. Then the accident happened and the bike was gone.
With the replacement, the lowest was a 42/24, which didn't cut it. I replaced the 6 spd with a 7 spd with a 28 tooth. That worked except the 52/28 was not an option as it should not be.

The biggest difference for me was the riding to improve my condition (loosing over 25 lbs and gaining strength). With a light bike and less than the ideal lowest gear, I can still get by.