Dead Rising- http://image.com.com/gamespot/images/bigboxshots/6/928326_67383_front.jpg
Love the hand drawn style, especially the zombies. Also, explosive Frank.
Fallout 3- http://www.donkeybiscuits.com/images/fallout3_boxart.jpg
I probably didn't need to link it, but I did for the sake of continuity. Ominous, dark, and to some extent minimalistic. I think it gives a good sense of the game's atmosphere.
Oblivion- http://www.mobygames.com/images/covers/large/1143232181-00.jpg
See above.
Animal Crossing- http://www.lithcast.com/files/page0_blog_entry53_2.jpg
Bright, vivid colors, very friendly looking, and just like the game, offers absolutely no explanation as to why you are the one lone human (minus friends) in a village full of big-headed talking animals.
One of these things is not like the others...