Thanks, WestPablo, I will definitely take a look at those deals.

CrankyOne, I live in the south San Francisco bay area (San Jose, to be exact). I'm 41. The only real issue is my left knee, which throbs a bit if I overexert it. The pain itself isn't a big deal, but I want to make sure that while I'm riding I'm not also wrecking my knee for good. Sometimes the ankle acts up slightly too, but not as much.

The bike I have now is a Jamis Beatnik in single-speed coaster mode. It has one of those wheels that is fixed on one side and coasts on the other, you just have to flip it around. I tried riding it fixed for a while but didn't perceive any real advantage to it personally, so I flipped the wheel back to coast mode. I got it maybe three years ago. Anyway, it was fine in the previous place I lived, which was totally flat and my commute was fairly short. I've been missing having gears though, I'm not in love with fixies or anything like that.

The south bay is actually very flat, but the thing is you are constantly going up and down overpasses, pedestrian walkways, etc. So they really aren't challenging hills, but it's enough of a challenge for me with no gears.