I know I'm very late, but if you want [if anyone wants] to get a Nintendo product the time would be now. They are on an uphill roll at the moment and seem to be producing some attractive games again. I've only played about five minutes of a newer Nintendo product (newer than the 64, my last new Nintendo product, so I sort of follow your gaming timeline), but following the discussion and news and everything on it, they are becoming an attractive proposition again.
I was impressed that Nintendo released a new version of Marios Bros. on the DS, based on the original concept. I hated the move to 3D worlds that have become too fashionable in the last few years, which really turned me off. But they seem to keep some games simpler now, especially on the DS. Mario Kart on the DS (which I played for a few minutes before my three year old cousin took it off me, thinking I didn't know how to play the game properly!) looked fairly cool too, incorporating courses from older versions and looking a clean and simple game from what I saw.
That's just my impression anyway. I am holding out for a while until I buy a new generation console or handheld, due to a combination of things. Firstly I've bought enough Super Nintendo products to last me years in the last year. Secondly I don't get as much time to play them as I like when university is on, so a new purchase at the moment would be a bit of a waste. Plus I want prices to go down a bit. And I have enough PC games to occupy my time as it is.
The Wii might be a really good buy down the track, depending on games. It's a bit too gimmicky at the moment, but is going in the right direction. You can download old games on it, but seeing as I have a Super Nintendo with just about all the games I want to have, there's not much point. There are only a select few Nintendo 64 games I want. Goldeneye, WCW/NWO Revenge, Mario Kart, Diddy Kong Racing, and a couple of others I forget.