I almost bought a PSP in order to play Medievil Resurrection, but luckily I didn't. I don't think I would've bought any other games. I still want to play Medievil though.

I bought a GBA in order to play Four Swords. I already had a DS, which you can play GBA games, but with four swords you needed an actual GBA because of the cable. Never used it since.

Other than that I've bought several games for my other consoles.