I recently upgraded to OS X Mavericks (I like to stay a year behind the curve :P) and was shocked to see the strange white dock. A grey I could (possibly) understand but white just looks horrible. Luckily a quick search of the web threw up cDock which simply gives back the dark look to the OS X dock. As well as letting you choose from a few provided dock themes there is also the option to specify your own theme along with background image, transparency, etc. There’s also a very handy tick box to bring colour back to the finder sidebar. Look and learn Apple, look and learn.