Gamecube is cute, I like it.
N64 is ugly. SNES PAL version is boring, but so much better than the quite-ugly American SNES.
NES, and PS1 (original) were ugly in their days, but now I think they have some kind of boxy retro look going that works well.
PSone is dull
PS2 is fat and ugly
PStwo is sleek and sexy
Xbox is butt-ugly, X360 is rather dull, but a vast improvment over XB
Wii is sexy, I wouldn't want it in black (though a nice sky blue would be very pretty)
PS3 looks sleek from some angles, but from others not so much, it's too complex in areas that are too easy to see.
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With that said.
GC > Wii > PStwo > NES > PS3> PS1 > SNES(PAL) > X360 > PSone > PS2 > N64 > SNES(USA) > XB