Reasonable on 01 January 2012
MS no as it's unlikely to return much even though it's hardly a risky option.
Sony no as the company is struggling and while it could be a decent long to mid term return it's fairly risky.
Nintendo no as while 3DS will do well I think Wii U won't be the hit the Wii was and I doubt the short to mid return would be that good.
In short - probably better options for investment around than these three.
Try to be reasonable... its easier than you think...
