woo-hoo! 5th! =P
Seriously, though. You rank schools after you interview for a reason. *All* the schools in Texas will give you the necessary medical education. Some schools will appeal more than others for different personal reasons and how they present themselves to you. They're shopping for you as much as you are shopping for them.
I picked Tech because it was closer to my family, and its nice to have that support in medical school. Plus, I'm familiar with the area and its an easy place to live.
There are also some other things to consider that make each school appealing. For example, Tech is pretty traditional in its curriculum. Galveston, on the other hand, is very problem-based learning oriented. (Houston does this as well, but not to the same extent, so I understand.) San Antonio also has the benefit of a unique clinical program that starts in July to help students become oriented with medical ethics, taking histories and physical exam.
I say, apply to them all, and rank them as you interview. Its YOUR impression that ultimately counts. =)