I recently bought a 15" Dell XPS, and I'm totally in love with it.
Personally I went for 15" because it's small enough to fit in my backpack, yet big enough to program on. If you're only using it for school work, I'd suggest looking at the 13" one.
Also, make up your mind about what you want to do with it. If you honestly only want to do schoolwork on it, a 1000$ laptop is more than enough, and you sure as hell don't need a macbook
