There used to be tech in interior California which is an inexpensive area. Sierra Online/Sierra Entertainment was a notable example. The Grass Valley Group was another.
Paul Graham's "How To a Silicon Valley" [0] has the best recommendations I've seen.
That said, there's a bunch of strength to @pg's points and conclusions. Portland and Boulder as potential tech hubs sounds about right. It might be possible to build out elsewhere -- Rochester and Buffalo in New York were technology centers, once, and though it's small, Burlington, VT, has much of the right vibe (though possibly too harsh winters) for tech.
I don't see the sweat-and-mildew belt -- the midwest -- really doing much. There's too much about getting outside and actually clearing your head, which the vast expanses of overhumidified prarie (or frozen tundra) don't offer. Though the land is cheap, and a few college towns (University of Illinois, University of Iowa, Notre Dame) might manage to create some centres around.
I'm also not entirely sure Chicago ought be written off, though I suspect it would take a tremendous amount to turn it around. On the one hand, it's lower-cost land, nearer East Coast centres, with good natural transport (air, rail, ship, truck) for various industry. On the other hand, the weather's little different from Ithaca or Pittsburgh, and the politics are interminable.
The flexability of pretty much doing what you wanted in California in the 1960s, 1970s, and 1980s is hard to beat, and that's continued to pay off. Though I'd argue those benefits are now largely gone.
The role of a cheap housing stock and/or the ability to pick up and create a long-term plan with a large set of land, say, in Chicago or Detroit, seems interesting though.
Paul Graham's "How To a Silicon Valley" [0] has the best recommendations I've seen.
[0] http://www.paulgraham.com/siliconvalley.html