Candoo? isn't that those kids products or is that Kandoo?
AudioBullet is unique, average size -- quite good.
Sellspace, interesting, not sure what it'd be used for though.
candoo.net - no clue about that one.
audiobullet.com / .net - i think that is a good domain you might be able to make a nice site from it or maybe even sell it for some money.
sellplace.net - this one might be ok i think it would be good if you owned the .com