I think the quality of the graphics depends on the genre, and how the game is shown.
Borderlands, even though it doesn't look realistic, I still think it looks quite nice for the way the art style went.
Minecraft, has bad graphics in terms of most First-Person games, but in this way makes it what it is, with better graphics the game play would be diminished.
EndWar has good graphics for a RTS game, however in most other games they might not be percived as such.
It is hard for me to find a game with bad graphics, because it depends, as I said on the genre, the art style, and also when it was made. Even 8-bit games can have 'good graphics' depending on what they are trying to do.
Not sure and answer to OT was anywhere in there, but I've typed to much to not post now.
EDIT: I suppose a game with 'bad' graphics would be one that has badly melded textures, or colors and textures that insult the eye.(Not Many)