Even though I am a Mac user myself, I really do like the flat look of Windows 8 and Windows Phone. They're very minimal and work every well in user interfaces where things need to be kept simple. It's a shame Apple themselves don't follow this style even though they design their products with a minimalistic approach.
When I do design work I always like to follow a metro kind of style, flat design is the current trend. So when designing something new I look at other examples of Metro design. Here are 15 examples of some awesome flat metro designs.