Ah, the old Game & Watch. I still have the Legend of Zelda and Donky Kong Jr unit's.

On the PSP, DS front. I don't think you can say which will be the most succesful when nither system is out worldwide yet. Nintendo may be the master's of the handheld market but then they dominated the console market back in the 90's until Sony came along with the Playstation so I don't think you can rule anything out. My DS arrived yesterday but that dosn't mean I won't get a PSP as well.