I left the service last year. I started out enlisted as a medic in the Army Reserve, finished college doing ROTC and was commissioned as a 2LT in the Infantry. I went through Airborne, Ranger, Pathfinder, Scout Platoon Leader Course, and the Special Forces Qualification course before I decided to get out. I am now in law school. I wanted to make a few points after reading your post. I want to make sure you are not decieved by any recruiter that will fill you with BS just to get you in. I had alot of unhappy Privates as a platoon leader that were not motivated when they got to their unit.
1) If you are in the Army Infantry, forget college while you are in. You will be deployed 6 months out of the year and will never be able to complete a class. College is given as a re-enlistment bonus, soldiers are given a year to go to school if they re-up after 4 years or so. Not until then.
2) If you want to go to college, then go. If you like the military do ROTC. There is no commitment and you can check out all 4 branches of the service. OK, so maybe you are not ready for college, many of my guys were not, so they joined for a few years. Just don't lose sight of your own objectives. The military can be a trap. You get a few bills, a girlfriend, and before you know it...20 years later, no college education, and 3 kids and a fat wife. You'll see what I mean.
3) If you go in the Army Infantry, select RIP, and don't let a recuiter tell you it is not available or you can select it at your unit. Once you are at your unit, you will never get anything, EVER!!! You can select Airborne training as a sign up bonus (usually), and guaranteed RIP. RIP is Ranger Indoctrination Program. It is after basic and it gets you ready for a Ranger BN if you pass. Even at the Ranger Battalion, many do not get to become Ranger tabbed. The competition for slots is hard, and only about 50% will make it. If you fail, they'll ship your ass out to where ever the Army needs you- you'll have no choice.
4) Once you become E-4 promotable, you can select to attend SFAS, the Special Forces Selection course. This is open to any MOS, not just an Infantryman. Cooks, Mechanics, anyone.
5) My dad was a Marine and he is proud. I look at my time in the Army like the movie Stripes, it was pathetic and I have only a few proud memories. I can't endorse the Marines, but they seem to stand proud on their own.
6) If you do go Army Infantry...avoid the Mechanized Infantry like the plague...you'll see...that is where the broken and tired go. Too tired or too broken to walk.