Using anecdotal evidence I don't know a single male aged 16-35 who games primarily or mostly on the Wii everyone seems to be on XBL or PSN , that's not to say that they don't play the Wii at all but it's not their main console of choice.

Is this the case where you live or is the opposite or a mixture even ?

The guys I know who have it as their primary console are all over 35, except my son who wants a 360.

I don't know anyone of my age range(15-20) with Wii.

We are six next-gen gamers, aged 17-19, 5 PS3 owners (well, 4, I'll be one in a few weeks), and one X360 owner. The Wii is popular with adults here...

I know three people who own a Wii, one of which uses it primarily because its the only console he owns (it is his kids' console though, birthday present). The other two own 360's and one of them a DS as well, the latter is used the most by her and the other guy plays mostly coop games on the 360 with me and another buddy.
I know (like you said) that this is anecdotal, and evidence is there to support that most Wii owners are in fact adults.
Anyway, my region/country is one of those that hasn't really embraced it the way many others have so it is in no way representative of the world at large imo.

Those I know mostly has the Wii as their preferred console, some of them has the 360 and one has a PS3 and they are all above 20

I'm 44 and I don't like Wii, but there are many my age excited about Wii and play with their young kids.

6 Wii

4 360

1 PS3

off the top of my head.

All 25-26.

So.  Fairly even i'd say.

No clue what my "primary console" is.  PS3 playing PS2 games at the moment hah.

I only know one person with a Wii, my sister. She also has a 360, and MY PS3 :D, and a DS and a PSP. As well as a SNES and a Dreamcast a plug away.

Spoiled bitch. :D:D:D:D

i only play games with my cousins and they have 2 PS3's in their house, and my friend owns PS3 as well, i am the only odd one out.