What MOS interests you the MOST?
I have served on each: Active Duty, the National Guard, and the US Army Reserves for 11+ years, and counting. I have deployed several times to the Middle East, North Africa, and Central Asia. Seven of those years were spent in the infantry, and the last four have been in Intelligence. At the same time, I've built a decent civilian career (9 years) in Information security and intelligence consulting, and I've gone to school for a few degrees!
All told, my military experiences and lessons have been the best in my life; and I'm a HUGE advocate of service to your nation in the Reserves or Active Duty!
Like I initially asked, the first step is determining what field you want to work in (This is what YOU want, not what some recruiter says to you). You should also take the ASVAB aptitude exam, as soon as humanly possible, to figure out what you're qualified to do.
If your scores are high enough, I would highly suggest picking something that requires at least a SECRET clearance - the higher the clearance, the better the job! The clearance will also be worth a lot of money in the civilian job market. Keep in mind, there are also very nice bonuses for intel folks at the moment! (all types! HUMINT, ELINT, SIGINT, MASINT, etc)
If you have any questions at all, feel free to ask them, and I'll do my best to answer them. You can ask here or in PM, whatever you prefer.