I, too, went to a university, was gone for several hours during the day, and kept a perfectly happy young GSD. She stayed in her crate while I was gone, and when I got home we'd play hard outside and run. The thing is, they HAVE to get plenty of exercise, or they get destructive. And they are very prone to seperation anxiety. They're extremely emotional dogs, and some dogs will have seperation anxiety when their family leaves, even if it's for the day. I know Luna would tear my room to shreds if she was out of her crate. I suggest really researching the breed first. Having a dog is great even when you're in school, but you need to ask yourself how much free time do you have to devote to the dog? Are you an athletic person, or someone who would prefer to lay around in your free time? With Luna, she'd get a good hard run and play for an hour, two to three times a day. I know during my finals, it was a lower end of exercise, but I'd always try my best to make sure she was happy. Just read up on the breed and their requirements. They're great dogs, I wouldn't trade her for any in the world. She kept me so much more relaxed during school times.

The amount of exercises a GSD needs depends alot on how you exercise it.

I have a setup that allows me to fast trot my dogs at about 9-10 mph while I ride on my bike. This way 30 minutes every 72 hours can be enough.

The problem is being alone for too long each day. I think this is the limiting factor.

Please be aware that they shed, a lot and all the time.  It is called "fur"niture for a reason. 

Also, listen to the others.  Be very clear and honest with what you are expecting out of the dog.  All dogs are companions, so that should not be the criteria.  Here are some questions to ask yourself.  Based on how you answer them, that will tell you what dog is right for you.

Outside of school/work, what do you do with your free time?
     Are you into the outdoors (running, camping, hiking)?  GSDs love the outdoors lifestyle.  They love to be on the go.
 
What about if you leave for vacation/medical emergency?  Who will always be able to be your back up for the dog?

If you move out and into an apartment, many places will not allow GSDs.  Are you willing to do whatever it takes to keep the dog with you?  Never, Ever, go into getting any dog with the "if it doesn't work out, I can always find the dog a new home."

Define what you mean by housetrained.  
        Any dog will go to the bathroom in the house if you miss their signs.  This does not mean that the dog is not housetrained; this just means you missed the dogs request and the dog could not hold it any longer.
        Housetrained also means:
             What does the dog do when you are not there (lay and wait, cry, destroy).
             What does the dog do when someone comes and knocks on your door.
             What does the dog do when you have a friend over.

Financially, dogs in general can be expensive.   I recommend budgeting around $125 or more a month for a large dog.  This covers food, vets, toys  (my dogs will put me in the dog house without remembering those).  Add more for training.

All GSDs require training.   They can be a very large, powerful, and destructive dog without this.  No matter were or how old the dog you get is, plan on professional training (more than what Petsmart delivers).  Both you and your dog will be much happier.  "A great dog is a well behaved dog." 

Rescue dogs are a great way to start.  Look around.  Asks lots of questions.  If they hesitate to answer you (this is not the same as not having the answer), this is not the correct place to get your 1st dog. 

Good luck.  GSDs are a wonderful breed.  You are in the right place to get good, experienced information.