i keep ones that i really enjoy and trade ones that i enjoyed but just not as much as the ones that i keep.
for instance, heres a list of al the ps3 games i own and ive owned but traded in.

:::I OWN AND ARE KEEPING:::
Uncharted
Uncharted 2
bayonetta
final fantasy 13
Red Dead Redemption
Fallout 3
Star Ocean Last Hope International Edition
Metal Gear solid 4
Warhawk
Demons Souls
Valkyria Chronicles
Modnation Racers
Assassins creed 2
Bioshock
Ratchet and Clank: tools of destruction


:::IVE OWNED BUT HAVE TRADED IN:::
Call of duty modern warfare
Call of duty modern warfare 2
Call of duty world at war
Heavy Rain
Dead Space
Resident evil 5
Viking: battle for asgard
Guiar hero 4
Rock band 2
Resistance Fall of man
Resistance 2
Motorstorm
Assassins creed
Killzone 2 (( regret trading this one ))
Eldar scroll: Oblivion (( regret trading this one ))
Disgaea 3


i think thats all of them. sorry for the list :)

I traded in some Snes games after I found out they were selling for a lot of money (including my beloved Snes Chrono Trigger and Mario RPG) and used the credit to buy some of the most awful PS1 games on the market. I traded in a ton of PS1 games for my PS2, too (so many, in fact that my PS2 was free--along with Zone of the Enders and The Bouncer).

Like some of you have said, I only trade in games if they are total garbage. And sometimes, I even keep the garbage. At this point, there isn't a DVD on my DVD shelves. They've all been moved into the closet as video games for various systems have taken their place.

Keep, in Australia trade in prices are ludicrous.

I try to only buy games if I know they will have replay value, or if they're really cheap, and if they're cheap the amount you can get trading it in isn't worth it

No need to apologize.  I LOVE lists.

My traded games are:

-Velvet Assassin (360)

-damn.  I expected this list to be longer.  I can't think of anything else.

I keep them but I think that in a few years I will traded them in when I simply have no time anymore.... I am already happy if I can finish a few games a year while I buy 30-50 of them...

Any game I like I keep, which is all most all of them.

See what most others have said, ie. I keep whatever I like. But that's pretty much every game I own because I only buy good games ^^

That said, I buy lots of games used instead of new. And that's from online auctions like eBay, not some Gamestop-style rip-off store.

I don't know how many others feel this way, but if I have a bad game in my collection, I feel as if my collection is tarnished.

I bought into the Far Cry 2 hype for instance, and I bought it when I was in the US. So when I found out that was crap, I couldn't trade it in, because the danish stores don't accept american games. So I had to suffer and watch it in my collection (maybe slightly exaggerated ), but one day, my mom came home and told me that she had tried it at a friend's place, and she liked it! So I got rid of it, and my mom got it for free!
And everything was awesome again. :D

It depends on how good a game it is... I generally keep them, but if I buy a game that hasn't satisfied me I don't sell it without thinking to much, the last games I sold were Madworld and Little Big Planet.

Always keep them, I only buy games I know I'm gonna love!