I went through the same thing with books. I used to have tons and tons of books, from fiction to reference, soft cover, hardcover, autographed, photography, etc. Then I got tired of all the space they require (not to mention moving them) and sold or tossed everything I didn't actually use or re-read at least once a year.
I should do it with games too, but they take up almost no space/weight and thus I just toss them in binder sleeves and forget about them, until a thread like this comes up.