Thoughts: the armed forces (frontline service anyways) are not a good career option.
Opinion: although I'd just say "don't do it", the Air Force is probably one of the better choices. I wouldn't join any regular armed service (I've considered the reserves though) just because I don't want to submit myself to intense resocialization, or in less sophisticated terminology, brainwashing. What I know of military resocialization is primarily the army and Marines (NEVER EVER EVER EVER EVER join the Marines), so the scope is a bit limited, but it's safe to say that there is still a decent amount of mental and emotional tweaking that would occur in any branch. Plus, you could get killed.
Carn, FOR THE LOVE OF GOD DON'T JOIN THE MARINES. Join the regular army and excel and join the Rangers or something, but the Marines is the absolute worst outfit you can possibly join in terms of your mental and emotional well-being.