lol, yep, interesting how american culture is so obsessed with guns.  But at least we don't have our heads in the clouds (fantasy :)

Using the same top 25 sellers sample, and again using the VGChartz categorization, the attach rates are:

Edit: Added percentage differences. I had to group FPS and shooters for the percentage difference to avoid a division by zero, as no shooter is present in top 25 for the PS3. Of all the possible groupings, this was the more relevant for the OP.

 So we can now say that the OP was wrong on two accounts.

1. The 360 user demographic is way more shooter (and RPG) orientated.

2. The PS3 user demographic is more diverse, ie, higher attach rates in more genres.

are you looking at the same stats?  it looks like a tie to me 4 xbox 4 ps3 and 1 tie. 

I'm not really saying xbox doesn't do better in shooters mind, but it's not really as much due to xbox's specific demographic as it is due to the American cultural demographic.  These stats don't really reflect that though.

This is a weird statement as the xbox demographic is largely American (57% vs 38% for the PS3). So when you say "xbox's specific demographic", what are you talking of?

In other words the - statistic based generalizations, take it with a lot of salt - chain:

"I'm American" -> "I like shooters" -> "I buy a 360 and shooters on it"

makes more sense than:

"I buy a 360" -> "I'm American" -> "I like shooters" -> "I buy shooters for my 360"

In the second case you have to justify the second link, ie why the overwhelming american demographic of the 360 a priori, before the library content comes in.

 I joined FPS and shooter together because the OP was talking about shooters, not just FPS.

yes, but technically the other is just a conglomerate of categories as well. 

Either way, I think the op is right that neither system really has a radically different demographic.  I think the numbers that we need to run are how these games perform in each region.  Each region has a different culture and different interests.  For example, Americans really like shooter games.  So, with the 360 having twice the install base here in generally translates into better sales of shooters on the 360. 

I am going to put out the hypothesis that if we compared sales by region, the attach rates would be almost identical.  I'm too lazy to actually do this myself mind, but thats what I think would happen.

^In this case "Other" only contained Guitar Hero/Rock Band titles... for this sample of the 25 top sellers you can rename it "Music/Rhythm" in your mind.

As to your hypothesis, it's probably true, but you're probably mixing up cause and effect. Id est: the very different distribution of consoles between Others and America is more likely an effect of the genre preferences, rather than a cause of the difference in attach rates (Japan is a different story, for cultural aversion against foreign products and image problems of the Xbox users)

I'm sure cause and effect has something to do with it, but not all.  You don't get this lopsided of an install base off of games alone.  there's price, marketing, brand recognition, word of mouth, etc.  Price being probably the biggest prohibitive factor. 

Besides, the ps3 has just as many quality shooter games as the 360 so I don't see that really being a big differentiating factor.

@gergroy

I actually agree, it's not a one-way road, more like a retroactive system. And as Reasonable posted before, there's a certain inertia with the image customers have of the different consoles and their libraries.

But back to the OP: I think that both attachment and sale share data contradict the thesis that the genre preferences of the average gamer are more or less the same between 360 and PS3. In the specific, I can't see any reasonable way to deny that the average 360 user buys shooters much more than the average PS3 user, and that the average PS3 user is more diversified in his/her buying habits.