Whether you are going military or civillian, I would highly recommend AGAINST a degree in aviation. I know guys who have majored in English and Communications and they are now flying the F-15E and the AH-64A. Can a degree in aviation help you? Sure, why not? However, if you have a 3.3 and an aviation degree, and another guy fighting for that pilot slot has a 4.0 in economics or english, I have a feeling they are going with the other guy. Sort of sucks, but thats the way it is. GPA, and in/out of school activitys are going to be the most important factor. Oh yea, and your LOR's..........
Another reason I would recommend against a degree in aviation is because you dont want to limit yourself. When your first starting out, flying is the greatest thing since the individually sliced piece of bread...However, one day this dream will turn into a means to putting food on your families table and food over their head. I've met quit a few pilots with amazing corporate jobs, who have packed up and left after about 10 years for various reasons...(Better pay outside of aviation, quality of life, wanting to be home more often etc...).
If you ever get to that point (which very well may happen and there is absolutely nothing wrong with that by the way), you dont want to limit your future opportunity by having a degree that isn't very applicable to anything else.
Furthermore, what happens when your 40 and lose your medical? (Refer back to the last paragraph about having a degree that isn't really applicable to other things).
Is getting a degree in aviation wrong? No, definately not. Your spending four years studying the field, and butt load of money for the next four years, so you want to make sure its something that will make you happy, and something you can academically excell in. And like I said, right now its prolly very hard to ever think you would get burnt out on aviation, or that in the next couple decades you may face a career ending health risk, but believe me the possibility is there. Just keep that in consideration and good luck.
What branch would you like to fly for by the way?