I'd buy the ones that you can't emulate.
Unless you can score some on ebay for reasonable prices, especially DracX for snes. I remember wanting it, just to have it and I played it and I said "damn, this is hard and it's not even fun." I emulated the game and didn't even play it through. Theres so much unjustice going on that it isn't even fair.
I will say that the PSP Dracula Chronicles game has pissed me off so bad that I almost went angryNintendoNerd on my psp.