A vote for all of the different styles (or "skins") was held in our IRC channel a while ago. Out of a score of 1-5, here is the list of the average scores:

Zephios: 3.5
Plastic: 3.125
Dark Angel: 2.9
NV: 3.84
SubSilver: 1.9
Windows: 2.625
Mako: 2.20968626957531731731692
Diablo II: 2.75
Ocean: 3.75
HUD: 1
Zephios Dark: 4.5