The average gamer picks up a few titles a year and may resell them game after or go shopping for low-priced used titles. But other gamers spend a good amount of time and money tracking down the rare games, the titles you can't simply find in a corner at the local GameStop. The banned games, classic Dreamcast games, complete NEO GEO titles... these are the things that makes the collector's soul sing.
There's also a slightly selfish aspect to serious collecting: the feeling that you're playing something that others will likely never experience.
But now, games that used to be rare are finding their way onto the Xbox Live Arcade, the Wii's Virtual Console, and Sony's PlayStation Network. What does a collector do when a treasured, rare game becomes a $10 download?