Great as a kid growing up. Super Mario, Kirby Super Star, Mario All Stars, Yoshis Island, Mario 64, Mario party 2, Perfect Dark, FZero GX, Metroid Prime 1/2 are the games I can think of off the top of my head that will always be timeless to me.
Today I have little interest in their games as they are dead set in appealing to the kids of today. But it makes sense....humans breed much quicker then it takes for them to die. Every 5 years there are millions of fresh batches of human beings that their parents are willing to introduce them to gaming. And it won't be until their late teens-early twenties before they go to other consoles/PC as their main fix.
Nintendo knows what they are doing, but the adult me wishes that just once, Nintendo would come out of their shell once in a while.