Originally Posted by strung
the army reserves is cool, but dont leave out the national guard either.
I've never even entirely understood why there is both the Reserves and the Guard, since they seem to mostly serve the same function. As to whether or not to join, get educated about MOSs like Gonefhshn said and find out what looks like a good fit. If your MOS is something mechanical but you get hitched up with the wrong kind of unit, you will never learn your MOS properly because it's not a priority for the unit as a whole, even if they have a slot for you. That's no fun. And double check whatever a recruiter tells you.
Another thing is that if you aren't 100% psyched about being in the military, it will not feel worth the commitment. Plus there is such a huge amount of people trying to enlist, they can afford to and will be very discriminatory about who they let in and who they keep. There was a time when you could fail PT tests one after another and have no serious consequences. Now, you fail two in a row, and you're out. That's in the regulations, but it's just now being strictly enforced even though it probably should have been all along.
I never served active duty except for 2 deployments to Iraq and a BS border patrol mission in AZ, and in retrospect I mostly wish I had just gone active Army from the get go. It's a major part of your life no matter what, and just easier when you completely immerse yourself in it as opposed to just putting a uniform on a few days a month.
And if you decide to do it, enlist for the 2 year minimum. That way you can make up your mind later whether to stick with it or not. If you enlist for longer to get a better signing bonus and later get cut loose for some reason, you are going to owe the government a shitload of money. It's a big decision, but get informed and think about it.