Is most of this stuff coming from Hard-Offs? I've got 4 locations near me, and not one of them has this much quality PCE stuff. All I ever see is F1 Circus, Fire Pro, Momotaro Densetsu games, baseball games and the other usual stuff. Only one of the Hard-Offs near me ever has more than that, but it's not much more. In a couple years... I've seen one PCE system there, a CIB Duo for 5000yen which is now mine, one CGII coloured controller, and a the usual assortment of PCE games that nobody wants. That's aside from the 2 worthwhile games I found; Poping World (CD) and Twinbee.
Likewise, I rarely come across any decent Mega Drive stuff.
My Homebrew Channel on the Wii is currently taking care of that for me. I usually just play Astroboy: Omega Factor on it anyway. I love that game.GC & GBA Player for 10 bucks. bought it only for playing GBA games on TV :)