I'd have to say PSO I&II GC was the rarest, I also got RAD, but I see that game all the time, and Disgaea, which I see all the time, just never for cheap. And I got Ring of Red, which I rarely see, but I don't know if that is just me or not. Oh, and Tsugunai, which I never see, but I don't think there is much demand for it (probably the same could be said about Ring of Red), since EBgames.com was selling it used recently for about $10.