I'll assume that your finances and work skills are something you've already considered, and that even with minimal work while you're here, you can finance a year in the USA with little (or no) income.
If you want to explore the entire USA, then logistically speaking, a central and Midwest location might make sense.
Kansas City comes to mind. There are some charming neighborhoods in which you could lease a house for a very reasonable price; the airport, although not brand new, is laid out quite well for quick in-and-out travel (it has three separate terminals, which actually reduces traveler congestion); it gives you all four seasons of the year; and in your case, it has a football team that really sucks, and you could have some fun telling them how to play REAL football (Rugby?).
Or perhaps Denver, Colorado (my neck of the woods). Housing prices would be higher than Kansas City, but wages would also be higher, there would be more opportunities for your skills, and the airport would probably offer more direct flights to more places. And in my (biased) opinion, the Western United States has some great places to visit - a lot of national parks, mountains, etc. (And the words to the song, [i]America the Beautiful[/i] was written from the top of the 14,000+ foot Pike's Peak, 70 miles south of Denver.)
Perhaps I selected those two locations because I'm intimately familiar with both, but they actually do make sense to me.
Chicago might be a pretty central location, but it's a pretty big city and probably more expensive. Maybe the Dallas Fort Worth area. Or maybe Austin. From what I hear, Austin, Texas is a very tech-friendly city.
A location on the east coast, however, would afford you closer proximity to the major population centers. Since I've spent so little time, myself, on the east coast, I can't comment on what might be the best location to serve as a base. But the REAL USA is more than just the major population centers. (The same might apply to the west coast.)
There's so much to see and do, that it would be hard in a year's time. Perhaps list the kinds of things you want to see and do, and make a selection based on that.
Visas and work permits - I have no idea. But a search of our State Department's Web site might give you some answers.
http://travel.state.gov/visa/temp/types/types_1271.html
If I have more thoughts, I'll post later.
By the way, if you choose either Denver or Kansas City, shoot me an e-mail and we can discuss them further.