If we're not talking about emulating or anything, I think I'd pick the Saturn. It has the best of both worlds - fast, lush 2D games and inventive polygonal games. My memory is of course tinged with nostalgia, that being the first system I legitimately saved for and bought during launch, but I still love the games and come back to them often. NiGHTS is like a living virtual world that I always like to escape into, and games like DARK SAVIOR, ASTAL, SHINING THE HOLY ARK, VIRTUA COP, MR. BONES, the PANZER DRAGOON franchise and even SONIC R I still all really enjoy today. Give me a NES, SMS, TG-16, PSX, DC or a GENNY and you'll hear no complaints from me either.