I play my Wii nearly everyday. I log on and I look at the "Check Mii Out" channel and the "Everybody Votes Channel". Those items in themselves keep me coming back to the wii. In fact, I don't know that I would play the wii at all if it wasn't online.
I think that once SSBB comes out that a lot of "hardcore" gamers are going to want a wii. Next comes Mario Kart Wii and then after that will be animal crossing. Nintendo is only bound to grow.
I've always stuck with the nintendo and I feel my game playing time has been well spent. Whenever I play the nintendo it is with friends and family, not alone in a dark room.