While the name is a bit cheeky, "Metro Sexer" (and similar "Metro" style themes) focuses on the Windows Phone/Metro design language that Microsoft pushed during the Xbox 360's mid-life.
(community trends rather than official ranking — representative examples) xbox 360 aurora themes best
A theme is only as good as the media filling it out. Use these tricks to make any skin you choose look absolutely incredible: While the name is a bit cheeky, "Metro