The DS reminds me a lot of the Game and Watch games back in the old school days.

I personally don't have a DS and don't really want one. My friend let me borrow his and I really can't play w/ that thing (lol). The touch creen is pretty cool though. OH! and to further answer your question, the old gameboy and gameboy advance games don't use the touch creen at all, only DS cartridges.
