While not part of the system BIOS almost every officially licensed megadrive game starts off with a license screen from Sega, it was my first system which effectively had a boot screen.
As for the "CDs invented boot screens" no, game boy most certainly didn't run on CDs
Heh, for some reason I forgot the classic "SE-GAAAAA". I kept thinking about this X-Men Genesis game where it not only skips the any startup sequence, but the gameplay also starts immediately without a "press start" screen either.
Anyway, I want to amend my answer then to simply say NES is the best start screen. Press power and just start playing Mario or whatever. Startup sequences really suck.