Sega Saturn, specifically the PAL version. PS1 and PS2 are close behind. Gamecube and Dreamcast are next. I don't like the Xbox start up, but at least it's quick. PS3/PSP are ok. I couldn't even tell you what a PS4 or Switch start up sequence is, they just haven't stood out to me at all. Mega CD is pretty cool as is the Gameboy.