I live in a major metropolitan area and fly across the USA frequently.
Based on what I have seen it seems that the US buys the consoles in three ways...
Rich areas buy everything (with NJ and CT being the richest states in 2006 census data)
Middle income areas buy 1 console generally, with a small number of hardcore gamers supporting all three platforms. The majority of Americans live like this. The problem here is if other critera become more important than games; adjustments will be made.
Low income areas see dedicated casual gamers and 'dedicated' gamers. Casual gamers upgrade when they can justify the value in upgrading, by seeing great new ideas, or a continuation of what they like. Dedicated gamers wait until the hardware price comes down, then buy their console of choice, and 2-3 new games a year, and lots of cheaper, used games.
I think Nintendo is tapping casuals, dedicated, the rich (who are trendy), some hard core, and many middle income folks.
Sony is reaching the hardcore and the rich right now. I would go on to say that a hardcore game spends an ungodly percentage of his income on gaming...I did a survery of who owns what right now..my richest friends have PS3, my poorest friends have last gen stuff, and my middle income friends have either a Wii or 360.
Microsoft is starting to tap the dedicated segment, casuals, middle income gamers right now. For gamers who need the most bang for their buck, 360 is very close to it's percieved value, but not quite cheap enough.
The key is getting the hardware mass market, because the average American household (man and woman working) makes about $42,000. NJ is the only state that has been over $60,000 since this generation started (2005). Also consider, America has 300 million people. 75 million bought consoles last generation. Already 3/4 of the population did not buy consoles. Prices are higher this generation...implying less demand. Especially since some the 25th-75th percentile in American household income is like $25,000 to $75,000. I would consider $100,000 minimal for people who truly buy everything - highend computers, PS3, 360, Wii, DS, PSP, 9 controllers (3 extra per console), 6+ games per console per year, XBOX live, Wii shop games, PS3 downloadable content, high speed internet...$5000+ or so a year is nothing to sneeze at for the vast majority of consumers across the world, but reasonable for wealthy hardcore gamers. The problem is, 90% percent of American households make under $100,000...The figures are similar in England, Ireland, Japan, France, Canada and a few other markets.