Military
Go for it! I was in the Navy for 11 years, and while it's true that you won't get rich ($ wise) in the service, you can bet you'll never regret the experience. By the time I was 28 years old, I had been to the following countries in my travels:
Africa (1 week)
Australia (3x, 6 weeks total)
Phillipine Islands (9x, too many weeks to count)
Indonesia (1 week)
Thailand (1 week)
Korea (1 week)
Singapore (4x, 4.5 weeks)
Bahrain (6x, 2 weeks)
Mina Jebel Ali (2x, 2 weeks)
Midway Island (3 days)
Canada (2x, 2 weeks total)
Lived in Hawaii for 7 years courtesy of Uncle Sam....in fact, that's where I got the Turbo Regal bug! Been all over the U.S., too.
You can have your grad school paid for by the service, but be aware that you'll often have a 2-to-1 trade off; that is, for every year of school paid for, you'll owe the service 2 years of time. Of course, this may have changed over the years....
As an officer, you'll enjoy a much better quality of life than the enlisted man, but you'll be subject to MUCH more scrunity, and expected to shoulder MUCH more responsibility that your civilian counterpart. Also, you'll be expected to be man enough to take responsibility for your screw-ups, without whining of bitching. The buck stops with you.
Now the cons: you're putting your life on the line for your country, and sometime you won't agree with the reasons why you're going into harm's way. Living conditions can be less than ideal, the pay is not equivalent to the private sector, and you may spend long periods of time away from family and friends.
Would I join again? Yep- in a heartbeat. Do I have any regrets/ Perhaps a few, but not enough to change my mind. Do your research, and make your move.