My opinion is to sell the crap. But I recently "Converted".
I took a look at my shelves and thought "You know, I could sell these shitty games for good games!" And off they go.
I keep some bad ones (Such as some RPGs and so bad it's funny ones) but it's more for playing here.
If you did decide to keep them, maybe take the time to try them all? Spend an hour a day or so just trying everything out. You never know, you could find some good ones in there