Hi,
Don't know if you are still working on your decision but thought I would add something since I did my undergrad at RPI and grad work at CU, and also grew up in upstate NY (just outside Albany). Most of the things that people have pointed out here are absolutely correct. Boulder is significantly more expensive (800 if you're lucky up to 1500 for 1 br apts - you might be able to find a 4br house that you can split for 750 a month). This gets cheaper if you move outside of Boulder to a town like Longmont or Louisville, but those are about 30 mins from campus and traffic can be a pain. Boulder winter is definitely better than Troy winter in that it isn't as long, the snow is nicer, and not everything is covered in ice for 5 months (only a slight exaggeration). Also, if you ski, Boulder is pretty much unparalleled. Boulder has a decent bus system while RPI, as I recall, didn't offer much. Boulder is a much nicer city in terms of cleanliness, social activities, and food, though Troy is definitely getting cleaned up. Troy has easy access to NYC (about a 2 hr, $45 train ride from Troy to Grand Central) and Boulder has access to Denver, but unless you want to go to the theater or a show, there isn't too much reason to go down to Denver. The Adirondacks will always hold a special place in my heart and the lakes are amazing for swimming and boating in Summer and Fall, but the Rockies offer much more in terms of hiking, climbing, backpacking, etc. I found the social life in Boulder to be much more dynamic and readily available, though the undergraduate crowd can be a bit obnoxious, as opposed to the RPI undergrad crowd that is a bit more serious making for a more mature academic community (obviously a generalization). Boulder has a large Buddhist/hippy population, and they have recently legalized marijuana. Lastly, CU is way bigger than RPI in terms of students, which probably has an effect on interaction with professors, but makes for a more docile campus and community.
These are just some of my thoughts on the differences between them, let me know if you have any other questions.
