Yeah, Kameo was worth the $5, imo, if you didn't get it free from club.live like quite a few of us did. I think the bad reviews seem to be attributed (at least to some degree) to it being by Rare. It's still a solid game with a nice plot and the controls are good once you master them and make the puzzle parts fairly fun. I ended up playing through it twice as when I first got a 360 from my friend I didn't have it hooked up to the internet or set up an account so I replayed it for some of the GS. (I have the PH, but I really don't think there's anything extra included, if so it's nothing of note.)
SEGA Superstars Tennis... I got the comp disc bundle new for $5 at a yardsale the other year mainly for the arcade comp disc itself. I played the Tennis for like 30 minutes or so and didn't really care for it. Wouldn't recommend the standalone especially for $5 as you can get the comp disc for under that at GS.
I already got Facebreaker as well for $5 still sealed at a yardsale as well, but haven't unwrapped it yet so I can't comment on it. My friend played it and said it's not bad if you can get past the somewhat steep learning curve.
As for me, I'll probably pick up Tornado Outbreak or possibly Prince of Persia.