Best:
SNES
NES
PSOne
PS2
PS3
N64 - for the original system
N64 - the one where it promoted the various colored N64 systems
Xbox
Xbox 360
Xbox 360 Slim
PS4 (trailer made me save up for it)
Xbox One (trailer made me save up for it)
PS Vita
Game Boy
Game Boy Color
Nintendo DS
All Sega systems

It wasn't a trailer, it was a bunch of magazine ads for the Gameboy Advance. It would say something along the lines of "This is where my girlfriend showed me how to do it right," and it would how a boy playing the gameboy advance. I used to like those.