Hmm.. my top prediction is $80 with a game packed in, after that, I would say $60 as a standalone, but I do think having it without something included to push sales will harm it more. I do think they want to keep it cheaper than Wii Fit to try to market the price angle from multiple directions. As for with a system, there will be an arcade bundle with Natal for $250, the Elite bundle will be $350. Standard bundles may see a small price drop if Natal is $80. (Arcade to go to $180, old Elite to $280.) The non-Natal bundles will also be discontinued.
-dunno001
-On a quest for the truly perfect game; I don't think it exists...