Same boat here. I don't even own an actual CD player. I can only play CD's via a computer or my car, and since I have everything ripped to FLAC/MP3 and both also play MP3's and FLAC's the CD's just sit around.
I doubt that many of them are of any value. Doubtful it would be worth it to lug them to my local record shop to try to sell them, and I'm not willing to list every one on eBay and then go through the hassle of shipping them.
I think the two options I'm considering are:
1. Drop them off at the Salvation Army and hope they will take them.
2. Put an ad on Craigslist to have someone take them for free.
I'm leaning towards #2.
There are a handful that I plan on keeping. One's that I know are valuable and/or rare. I have those set aside.
I just have so many that I know I'll never listen to ever, and I know they aren't worth a penny.