I'm not trying to sway your opinion either way, however I just want you to learn from other's mistakes.
First thing's first. Find the MOS you want to do. That will narrow it down by branch. Unless you want to do grunt work, but it's not really for everyone. I was going to join up for a very specific MOS, Mental Health Care Apprentice (MHCA). That left me with two available branches, Army and Air Force.
Next, if you're fortunate enough to have a military ID card get in touch with your local base's Education Center (Army, I donno what the other branches may call it). Ask them what your options are, and what they would advise. This is a great, free, no-bs service for all MID card holders.
Also, try to find a soldier who all ready does your MOS. These guys will usually tell it how it is. Come to find out, I talk to an Air Force guy about the MHCA and he's just a receptionist! He went to training for like 46 weeks or so, just to have people sign in and take a number. There's a lot of BS jobs in the military. And the Recruiters (as you are aware), and also the Career Councilors (at the MEPS) will make them sound very enticing. "Petroleum Specialist," may sound nice on paper, but all they do is pump and transport gasoline. First, pumping gas is unskilled labor that no one will pay you for doing outside of the military. Second, I can't think of a bigger target then a truck-load of gasoline.
Always, military or not, have a back-up plan. Have something to fall back onto if things don't work out. Because the military, and life in general is known for breaking as many dreams as it makes. If you're strictly looking for a combative MOS, chances are few people in the private sector will consider that a "skill," and will not hire you based off of it. Whereas, if you go medical, lab, etc. there will be plenty of doors open to you once you decide to retire/not reenlist.
And just a little tack-note; the whole "go to college while you earn money in the military," thing is not a guarantee. If you are enlisting active duty you must be given permission to. You are a soldier 24/7 if you're active duty, not 9 to 5. So they need to know if you are unavailable from 6pm-8pm because you're taking classes. And a lot of the soldiers that I go to school with miss about half of their classes because they're staying after to do stuff. That said, this is just one more reason to look for a "kush job." Not only will you have training to work in the private sector, as outlined above, but also, you'll have a decent schedule or 9 to 5. This will enable you to pursue more things inside and outside of the military. Plus, fewer slots are available in those jobs. So you won't just be a face in the crowd. You'll be recognized for your hard work.
Finally, continue doing this, asking questions. The more information you have the better off you are.
Hope this helps.
(And no, I'm not, nor have I ever been in the Military. My old man just retired after 23 years in the US Army. First 8 as a combat engineer/sapper, and then as a combat medic. That's where I got most of my information from, and just from my experience. Plus, I live in a kind of poor area of Colorado. So a lot of my friends jumped on the military wagon after graduation. Some of them have had better experiences than others, so there you have it.)
Edit: If you're joining simply to kick butt and take names. Go Army>Airborne>Ranger. You are literally paid to shoot a lot of bullets and work out. Plus, this is an entry-level "elite" status, and is the first step to "special." You could definitely go Green Beret after the required amount of time "adjusting to army life." The Beret's just won't take you unless you have, i think, 4 years in the army. These guys bleed and breathe kicking butt, and are much more highly trained than the Marine grunt. However, this takes a lot more work then most people are willing to put forth. So if you want to be the best of the best, then go for special. But the drop out rate for those schools are exponential. It's also worth noting that the Air Force has the most special forces units. If you're really fit, and really adventurous you may want to look into CSAR (Combat Search and Rescue.) You'll be rescuing downed pilots no matter where they crash land. It will take you to the tallest mountains, hottest deserts, deepest oceans, etc. If I had the guts to do it, I would. I heard part of their training involves a mock crash scene at the bottom of this huge pool. They strap you up with a lead vest and drop you in on THE OTHER SIDE. You then have to walk along the bottom of the pool and grab the dummy. Then swim back to the surface, all on one breath of air.
