<p>OP,
I see that you are from California. Have you visited either school? Personally I prefer Duke to Northwestern, but plenty of folks will have lots of good reasons to feel the opposite way. </p>
<p>One very obvious differeniator is the weather. If possible, visit Evanston in January or February. If you’re okay with the cold at that time of year, then Northwestern perhaps goes up a bit in your calculations. But don’t underestimate the cold and how that affects your day-to-day life and this is especially relevant for one coming from California. Also, note the differences in academic calendars. Northwestern tries to minimize the weather impact via their quarterly system, but this also means starting later (9/22 this year) and finishing later (6/11 in 2010) than most schools. Some folks will like that and others won’t.</p>