Personal preference really. The bigger single door will be more likely to blow in during a hurricane or other severe weather event but that's really the only downside. As long as it's rigged right it is not any less reliable. I prefer the look of the double doors but have a big single door on my house.

This post was edited by mosquitogang201 on Fri, Jun 27, 14 at 10:04

A little late, but for a 2 car garage. I would want 1 wide door. If you happen to pile stuff on both sides, you can put the car in the middle.
I had 2 doors on an old garage behind my house. 1 door was 2' behind the other. I framed out the garage and put in a 16" oh wood door. By myself. Boy that was fun!