I'm really gonna have to go with the NES. (Mostly for personal reasons, not gameplay.) I'm unable to play 3D games because I get insanely sick with motion sickness, and side-scrollers are the only games I can play, so now I'm just kinda stuck in a perpetual state of nostalgia with NES games. Love 'em.
RE: COMMUNITY ENGAGEMENT: What Video Game Console Is The Best?