Dreamcast I think was the point when 3D visuals were consistently acceptable. No tearing, acceptable draw distances, decent textures and solid frame rates. Also the introduction of 640 x 480 as standard rather than 320 x 240.
I'd say 16 bit was when we got that consistently for 2D (no flickering etc) but 8bit games have aged better than most 32bit 3D titles.








