You should definitely apply to all the schools in your legal state of residence (if you're a Texas resident then you're one lucky bastard). As for the other 100+ schools, LOCATION should be your primary criterion for selection of schools. Basically you should just pick regions (SE, NE, etc.) of the US where you would like to live. Then it's just a matter of investigating particular schools in these regions; you should focus on private schools, since these schools typically do not have any preference for in-staters. However, there are a few public schools that accept a lot of nonresidents (U Mich is a good example). If a public school is obligated to offer 85% (or more) of the spots in the entering class to state residents, don't even bother applying there--you pretty much have to be God's gift to mankind (with a resume to prove it) to get in.
What should you look for in particular schools? The answer to this question depends on your own preferences. But here are some things to think about:
Curriculum: Would you like the school to integrate concepts for you, or do you want to build bridges between seemingly disparate concepts and facts? Some schools have a systems-based approach to the preclinical years, in which students study entire systems of the human body (e.g., the cardiovascular system), focusing on the anatomy, physiology, biochemistry, etc. of the system. Typically the first year focuses on normal function and structure, the second on abnormal function and structure (i.e., diseased states). Some examples of schools with this approach are Baylor and Michigan. Other schools are fairly traditional, in the sense that the preclinical material is organized into disciplines (biochemistry, anatomy, physiology, etc.). Some schools have a hybrid approach, in which the first year is traditional and the second year is systems-based.
Some medical students claim that the nature of school's preclinical curriculum isn't that important--everyone hates the preclinical years and each approach seems to churn out great docs. Even so, I have a preference for the systems-based approach; I just think it will make studying for step 1 easier, because step 1 (based on my limited knowledge of the exam at this point) forces students to integrate concepts and facts, kinda like the MCAT only 50 times harder.
Do you want a compressed preclinical curriculum (1.5 years at a few schools, 1 year at Duke) or 2 full years?
Clinical Training: Look for schools that offer "hands-on" clinical rotations(i.e., students get to do a lot of procedures). Generally speaking, the more prestigious the medical school, the more assertive students have to be in order to perform various procedures themselves; the trade-off is that the attendings are nationally and possibly even internationally known, which means that letters of recommendation from these guys can open doors for residency. Also, county hospitals and VA hospitals are great for hands-on rotations, so you should look for schools that have teaching hospitals of this sort.
