Gleb Kuznetsov is a Russian designer that comes up with pretty gorgeous UI pieces for apps and web. He's got a pretty awesome portfolio with many great examples of how beautiful an interface can be. Check it out!
Here you can see a brief selection of his work. I really enjoy his approach on graphs, using gradients and glowing effects, which brings a "Tron feel" to it. For more of Gleb's work, please visit his portfolio at Dribbble! I hope you enjoy these as much as I did. Cheers! ;)