The first details of how much customization will be available for the Moto 360 comes from Wired: They state:
You'll be able to choose from three watch casings: silver, black, and champagne gold. Then you'll choose a band, which comes in two sizes, in either leather or metal. (Motorola's careful to not designate the sizes "male" and "female," but that's obviously the idea.) Lastly, you can select one of 11 watch faces, picking the one that will appear the first time you turn your watch on. There are a couple of new watch faces, and Motorola finally offers the gorgeous single-link band it teased in its first promo video nearly a year ago.
The article adds that Motorola will offer even more customization options for the Moto 360 after the Moto Maker feature is launched.