The only one I really can't find a game I like on is the Sega CD, the rest get played regularly.
Seriously? I know there's a ton of FMV crap, but there's good stuff on it - Sonic CD, flashback and Silpheed spring immediately to mind.
But what is there on the Jag CD that's any good?
Sonic CD is OK, but I'd rather play Sonic 2 or 3.
I don't have Flashback on SegaCD, but I do have it and Out of this World on 3DO, and I don't like them. I don't have Silpheed, I'll have to check that one out.
To be fair, if I didn't hate jRPGs with an unholy passion, Lunar would probably be half decent. Sol-Feace isn't bad, per say, but compared to games like Blazing Lazers, Radiant Silvergun and R-Type, it hardly justifies existing.
So far, this is all I have for Sega CD:
1.Lunar
2.Night Trap
3.Prince of Persia
4.Sega Classics
5.Sherlock Holmes consulting detective
6.Sol Feace
7.Sonic CD
8.Stellar Fire
For Jag CD, Blue Lightning is decent, Primal Rage is good as far as fighting games go, but it'd be better if I had a quality joystick. Dragons Lair and Highlander are probably good if you're into RPGs. Vid Grid is an alright puzzle game, if you like the music (and I do)... Nothing particularly stands out as being great on the Jag CD, but it definitely has games that are playable.