I think that the XBOX probably has a higher percentile of Hardcore gamers.
The PS3 has a TON of hardcore gamers, for sure but they also have a lot of casuals from the last gen that "upgraded" their PS2s - Not to mention the ones who bought it for a Blu-Ray Player.
I'll state a couple of cases that I know of personally to illustrate my point - I have an uncle who's a doctor, around 40 - he has 2 PS3's in his house, one for movies and one for playing racing games - he's the type who only plays racing games too (namely, gran turismo) so don't count on him to increase the attach rate of the console.
Another friend - owns all 3 consoles - By FAR prefers to play games on his Xbox so when a game is Multi-plat, he buys the Xbox copy - uses the PS3 for the occasional exclusives that interest him (Was not interested in LBP or Killzone) and as an upscaling DVD player.
On the other hand, Everybody who buys the Xbox, buys it to play loads of games - aka, a higher % of hardcore.
