Yup, I keep pretty much all of them. I like having a nice, small collection.

As soon as I'm done, it's getting sold. I have no need for collections, they just take up space (on shelves or harddrive), and I almost never replay a game.
In case I decide to replay it down the road, I can always buy it again, probably for less than I sold it for initially.
Other than a few games I'm playing now, I own absolutely no other games.

I keep the ones I like enough; the rest I usually sell or something.

this

The few times I did sell a game... I lived to always regret it.

I keep all my games and all my consoles too. Even if I dislike a game, I will keep it just for collecting, but that's not usual since I'm usually selective with what I buy and even the so so game usually have some redeeming factors anyway.

i keep em

No, never again... I did it once, and it was a huge mistake. I'll never get my N64 games back... : (

I keep them, all of them, good or bad. I have never bought a game that I regretted buying and played all games from start to finish (with the exception of a few digital games i bought and never finished)

I don't think i've ever sold or traded a game before... even the terrible ones :/ 

I generally keep them. That's because I generally buy only games that are worth keeping.