I'm voting for the Mega Drive purely for the nostalgia. When my brother gave me Mega Games 2 with Shinobi, Streets of Rage, and Golden Axe, I was absolutely over the moon
For me it's between the Mega Drive and the Playstation.
But the Playstation would be my top pick.
Gran Turismo, Tekken 2 and 3, Final Fantasy VII, Metal Gear Solid, Spyro the dragon, Wipeout 2097, Resident Evil, and many more.
SNES. I went to secondary school between 91 and 96 so most of my playtime was done there with school friends, then I went to university from 97 which was around the time PS appeared around here in Argentina; by then I was no longer interested in gaming so I skipped all those other generations. But most of the people down here had Sega Genesis/Megadrive, so it was hard finding new games for SNES.
I never owned a SNES as a kid which is a damn shame. For me it was the N64, and PS1 following closely behind. Game Boy also ranked high on the list but missing from the options.
I see not much love for the 3DO, I guess its price point was a thorny issue, but as a system in of itself, it was more than capable of bringing true 32 bit gaming home.. certainly a lot better than the competition at the time - Atari Jaguar, 32x and CD32....and in the initial years of the PlayStation and Saturn could have held its own till the M2 arrived...