Do you have a DC broadband adapter? Those are selling for $180, I'll be putting mine up soon. I will never play another DC game online, not even sure if it's possible. To be honest, I don't know why anyone would pay more than $5 for the thing, but I don't mind selling it for huge profits
I also was a bit surprised by SA2. I honestly only chose to sell that one because I have the GameCube version. I'm also a bit shocked Rez and Ikaruga both sold for more than their XBLA counterparts, which are both improved versions.
Also, if anyone is interested in selling their stuff, I shipped everything USPS first class through eBay directly. You will need a postage scale, but it generally cost me $2 to send a game, and about $4.25 if I added signature confirmation (which I did on anything over $20). I had no idea what to price shipping at when I listed them, so figured it might help someone out. Also anything under 13oz can do directly in the mailbox (games are between 6-9), so I never had to stand in line at the post office.