@TheOtterOne, I don’t know too much about Northwestern specifically. It’s very prestigious, and probably more widely recognized than Amherst college (although Amherst obviously is a very prestigious LAC).
Northwestern is within easy public transportation distance of Chicago, which is a wonderful city. It is also right on Lake Michigan if you like anything water related. As far as weather, the weather between the two is somewhat similar, but it is on average colder (probably about 10F colder) during the winter in Illinois, and always windy.
The two places probably get about the same amount of snow, but Amherst is in lush New England which overall is gets more precipitation than the midwest. Conversely, it’s also a little bit sunnier.
Amherst is in the middle of mountainous, woodsy massachussetts, not rural exactly because it is in a small New England town (with picturesque town square and all), but right next to two other small towns, where a total of about 30K students who attend 5 different schools live. As a result, although Amherst itself is small (~1600 students) it is situated in a large and vibrant community. The leaves changing color in the fall will definitely make you want to write poetry.
In my opinion, undergraduates get more attention at Amherst because its a small school with no graduate students, and it seems to be relatively easy to get research opportunities, and it also does very well at sending students on to graduate school:
http://www3.amherst.edu/~sageorge/outcomes.html
Because of the 5 college consortium, you do have access to all the courses from all the schools, when gives depth to a curriculum such a necessarily small faculty can provide.
It also has an open curriculum which means there are no ‘core’ requirements, only requirements in your major. That gives you the most opportunity to experiment as student.
However, I didn’t go there. Someone recommended it to my D at the beginning of her Junior year and she was wowed by it for all those reasons, and it has been at or near the top of her list since. She’s currently deciding between University of Michigan, Oberlin, and Amherst, but Amherst is pretty much a lock.
You will be able to see all of this about Amherst when you visit. Just make sure you learn more about Northwestern. Good luck!