I'll just start it off by saying that I absolutely *hate* it when console companies standardize the "look" of their system's games box art, like Sega Master System for instance with the grid background. I realize that they are trying to differentiate their games' look from the competition, so people know what they are buying, but it just doesn't work artistically. Seriously, people aren't stupid and will buy the right game for their system or return it.
(Though, I'll say that the early NES titles, with their stylized blocky in-game graphics actually had a certain charm to them, for the first little while. But I'm glad they changed direction early on.)
The best boxes were on the later NES because: A. They were the right size. B. They were the right shape (vertical boxes). C. Except for the small Nintendo Seal of "Quality" (har har), the art wasn't ruined by logos or standardized looks.
It was a really dumb move on the part of Nintendo to go with horizontal boxes for SNES and the standardized look.
Now, would you rather play this:

or this?

Phantasy Star was by far the better game, but you wouldn't know if by looking at the box. I'm sure this played a part in Nintendo beating Sega out in the 8-bit generation.
























