Seconded. Going to Northwestern has been a big leg up so far. Attending a top 20-30 school (especially in CS) may be the difference in getting an interview or not (where you can really show off ;)).
Informational question here from an onlooker:
What's the recent consensus about which schools are the top twenty or thirty schools in CS, especially for a young person with an interest in start-up Web service work as contrasted with Wall Street or Big Company work?
Also, U Illinois Urbana-Champaign, Harvard, Yale (rest of the Ivies), Caltech, UChicago.
I'm sure that there are others. Personally I'm a big proponent of the liberal arts education so I'd probably put schools with very good general programs closer to the top, but that's my personal belief.