Seeing as how I don't know how to use any kinds of guns, a melee or unarmed weapon might better suit me. I don't know how difficult it would be to figure them out, though. Anyway, if I was exploring the Mojave, I would want the All-American, because of its versatility and accuracy. If I was living in a city or town, then a .45 pistol or a hunting shotgun.
As for melee and unarmed, I would use either a thermic lance or a bumper sword (bumper swords are [censored] awesome).