Of the people(mostly coworkers) I know
only 1 has a Wii (and my brother has one 600 miles away, the only one I've ever played)
6 have PS3s
7 have PSPs
1 has a 360(technically he has had 4 of them though, HAH)
2 have xboxes
30+ have ps2s - guesstimate from just talking to people at smoke breaks(guitar hero is insane, 2 girls and one of their mother's bought PS2's and guitar hero with no intention of ever buying any other games)
and 2 DS owners
EDIT: However, I don't think the stores have a lot to do with its success, it's marketing is very good, along with it being the "in" item right now(I didn't say it was a fad, back off) and LOTS of word-of-mouth advertising as well, kinda like that Guitar Hero thing(^^up there) where one played it at a friends, bought it, then the other played, bought it, and so on.