Sony is doing its best to convince consumers that its black evil looking system was made by Lucifer himself. They want to look cool, hip, and intimidating. They want you to think that other systems cower in fear when the PS3 enters the room.
Sega tried the same strategy in the early 90s and it relegated them to 2nd place. After all, evil satanic looking things do appeal to some, but the Wii has a broader appeal with its angelic benevolently blue halo. And you know, good always triumphs over evil in the end. This is a system that is more family friendly, both in games and in the advertising. Parents who are thinking of gifts for little Billy this christmas are watching the commercials and with the Wii commercials they see two friendly Japanese guys demonstrating fun games to people; now contrast that with the PS3 commercials with creepy satanic dolls and dark disturbing imagery. Which do you think the parent is going to opt for out of these two?
And as for the 360, I guess they are neutral or some shade of grey, like purgatory or something....