I'll chime in as to why I chose Cornell over both Stanford and Berkeley. I'm interested in condensed matter experiment (playing with nanostructures in particular), and Cornell just destroys Stanford physics and Stanford applied physics in terms of interesting and high-profile CME/nanostructures research, and Cornell's facilities blow Stanford's out of the water. The CME rankings are absolute nonsense with regards to Stanford!! Berkeley is the only school that can try and compete with Cornell's facilities in terms of nanofabrication (maybe also UCSB once their new facility gets on its feet), but Berkeley's Molecular Foundry operates very differently than Cornell's CNF. CNF just blew my mind with all of the equipment available, and once you are trained and get a badge, you can go in there and use it any time of day or night, 24/7. At Berkeley, you have to submit an application to use the facilities, have it approved for funding, then schedule a very specific time during business hours. Yes, you don't have to work first-come-first-serve like you do at CNF, but CNF just seemed to have way more freedom and flexibility, and WAY more cool stuff!
I also found the environment at Cornell very friendly and the most active and encouraging towards interdisciplinary research. Everything about the department seems meant to foster collaborations.
Also, some of the most high-powered research groups in CME/nanostructures are located at Cornell. For nanotechnology, I think it is absolutely the best in the country.
Did I mention everyone is super friendly here?!
If you can't tell, I love Cornell and I'm having a great time here!