Ok so.........

[crazyhorse]

I'll have to +1 on what everyone before said.
In the Air Force, working on the heavies translates DIRECTLY into the civilian world. If you plan on going to school, if it's remotely related to your MOS the military will help you. If you didn't do so well on the ASVAB, by all means, retake it. This will help you get a better MOS. Try to find a job that will translate into the civilian world. Especially if you don't intend on being a "lifer".
In the Army if you don't choose an MOS before basic, you're infantry. You're the man on the ground with a weapon.
The military life isn't for everyone, it wasn't for me. You may fall in love with the lifestyle, you never know.