One question, though. All of you buttons seem to use the "grayed when pressed" idea to show when something has been selected. This works out really well because it lends to the illusion of a button being physically pressed down in a virtual space when selected. Why then is your checkbox reversed? The empty, presumably default checkbox is grayed, and the check appears in the non-pressed box instead. This is counter to the rest of the buttons, in that if a user wants to enable a thing, they have to click on the grayed out box to ungray it and change the button to its "presssed" state.
In the grand scheme of things this is a teeny tiny nitpick. I was just wondering if you did that on purpose (with the idea that "checked" is actually the default) or if it just wasn't considered important. Either way, keep up the great work!