I've been holding off on playing any old Nintendo games in any form ever since I heard about the download service so that I can still have them to play on the Revolution.
I'll probably buy my whole game library again. Ooooh, Nintendo is making me pay twice for my games - and willingly! Smart. Most of my games from the Super NES and up are the exclusive first-party games, though my NES probably won't last forever so hopefully the games I have for it will be included. While big companies like Konami are likely to be on board, if any are, (so I won't miss out on buying Contra), I fear for other NES games I once owned from smaller/gone/absorbed/where-are-they-now companies (like my beloved Blaster Master from Sunsoft).
But more importantly, I'll be buying the games I feel I should have but don't.
Being the Nintendo fan that I am, I will probably get all the Mario games (I never did own All-Stars), the Metroid games (why did I sell Super Metroid? WHY?), and all the Zelda games (I never did own Zelda II and Majora's Mask until the Collector's Edition Disc...and now I question why I'm buying them again)...
Therefore, some games I'd be buying just for the sake of having them, more for the sake than replaying them the umpteenth time. Nintendo games have often been remade already (the main Mario games have all been remade except for Sunshine, all Zelda games are playable on the GameCube in some fashion...) so I wonder if the games I would actually be playing for the first time would actually be a small percentage of what I'm buying.
I really hope they don't charge too much...I'd be such a collector and much more so since it'll probably be very convenient. Even at the impossibly low price of a dollar per NES game you'd see me willingly put down $700 for the whole official North American NES game collection... I'd be happy, but I'd be broke.