I'm happy with my "collection" but I am slightly bummed about what has happened to the hobby.
I started "collecting" in 2006, and I have less than 50 each for NES, SNES, Genesis, PCE, probably around 30 each for those. The part of the hobby I enjoy is learning about new old games, or getting reacquainted with games I played in the past, and taking my time to enjoy them. So I don't go out and drop $$$ on big lots of games or have some checklist of must haves.
What bums me out is how the list of games that become "collectarded" in an inflated way for the original keeps growing, occasionally throwing the siren song of "better buy it now before the price goes up" that I have to fight against. So I content myself with flash carts, CD-Rs, and emulation for games in that category, and keep a mental list of games that are expensive but I keep and eye out for when good deals present. Playing the "slow game" that way is more satisfying than using my wallet like a club like the collectards and keeps the "hunt" part of "collecting" interesting and satisfying.