I think Silicon Valley, Boston, Seattle, and NYC are in the top four. Except for the Valley, people argue about which city is in which spot for 2-4 (they all ha

I think Silicon Valley, Boston, Seattle, and NYC are in the top four. Except for the Valley, people argue about which city is in which spot for 2-4 (they all have their niches), but it seems unlikely that Portland -- although it's a wonderful place to live and a solid runner-up -- could make a solid case for the top four.