I don't have much experience here, but I'd just do the three single doors, and if I were to build a house, I'd do three single doors as well. I've never seen why people prefer the double door, but I guess that just personal preference. My parents house has two 9' wide doors, and there is no navigation problem at all. However, since my dad stores his Charger against the back wall, I can see now why two double doors might be handy... although the garage would then be smaller overall.
Anyway, if I were in your position, I'd just do the three single doors. It'll look and function just fine. If you can though, I'd try to get 9' wide doors. My grandparents house has 8' wide doors, and while they're not hard to navigate in and out of, I like our 9' wide doors much better.