The difference in prestige among UVA, Stanford, and an unranked school is very difficult to measure objectively. You have to really decide what you want to get out of med school in the long run. You want to find a place that is supportive and gives you the opportunities to succeed. For me, this would include a low stress, non-competitive environment that will allow you to reach your potential as well as plentiful research opportunities in your desired field. I cannot stress this enough...UVA is very supportive and there is more or less 0 competition during the first 2 years - classmates constantly hold review sessions for other classmates...I haven't heard this as much at other schools. Second, you need to decide where you want to end up for residency. Yes, plenty of my classmates from the West Coast are able to match back there (UCSF for derm, etc - just check the previous years match lists) but it is definitely an uphill battle compared to going to Stanford for med school...just keep that in mind. Regional bias DOES exist...but if you are originally from the west coast and go to an east coast school, it is much easier to match to the west coast than if you have no ties.
Go to a school where you will be happy (both academically and financially), which will allow you to succeed (top grades, board scores, etc) and get into whatever residency you want. One of my undergrad classmates (1 yr above me) went to VCU (more or less unranked) for med school, killed it there (AOA, top board scores/third yr grades), and matched at MGH for urology. Clearly an unranked school didn't hold him back. If you are motivated and smart, you can go to any med school, do well, and end up where you want. Don't over-think the decision...med school is only 4 years and doesn't matter too much in the long run (residency matters >>>>> than med school).