Years of reading comments from our wise SDN medical students and attendings have me say this:
1) T50 = every MD school in the USA
2) There are some 30 schools in the T20, and if ask five people what they are, you'll get six different answers.
3a) As mentioned above, if you are interested in a career in Academic Medicine, the the research Powerhouses (ie, the Harvard/Stanford and Einstein/Keck/Emory classes) are for you.
3b) Even if you go to a Drexel/Albany or a Miami/Wake class school, you can still get into Academic Medicine
4a) If you are gunning for an uber-competitive residency location, like MGH, then the inbreeding of the research powerhouses can help.
4b) But you can still get into these places as per 3b
5) Lastly and most importantly, if you're interested in just a regular career as an attending, it doesn't matter as your salary will be the same if you go JAB in HI or Harvard, U WA or Miami, Albany or Yale.
The only people are care about rankings are starry eyed premeds and med school Deans.