You got 3DO? Thats cool.
Not long ago I listened this podcast from HG101 guys, were they talked about 3DO and some of its good titles. Episode 5. You can get it here:
http://hg101.classicgaming.gamespy.com/podcasts.htm
Some of the good ones I remember them talking about were Horde, Return Fire, Alone in the Dark, Super Street Fighter 2 Turbo, Road Rash and Star Control 2. I'd also personally recommend lightgun games like Mad Dog McCree (campy western) and Corpse Killer (campy zombies).
But whatever you play, avoid Plumbers Dont Wear Ties. Its trash-material.
EDIT: And no matter what everyone has said to you, you should try Night Trap