Including myself and friends (all within an 18 - 27 age range):
7 have Wiis
3 have 360s (two of them were bought during the PS3 launch)
1 has a PS3
For handheld, I know 1 person who owns a PSP and 5 who own a DS
Also a couple PS2s and Gamecubes.
I think a big concern of non-Wii owners (graphics and all that aside) are the controls. If you haven't actually played anything on the Wii it would be easy to be quite skeptical of the controls; however, (if playing the right game) getting any kind of hands on experience is usually enough to quell any control worries as well as to generally show how fun the system can be (i.e. casual gamers getting a taste of Wii sports).
In my experience, Wiis selling had less to do with the stores selling them and much more to do with word of mouth or someone playing a friend's system then subsequently wanting their own.










