I think you should consider the fact that mobile devices are driving user interfaces and often the evolution of the desktop user experience as well.
This because the big market players realise that users spend more time looking and interacting with their mobile handset more then their desktop. Apple and Microsoft recent efforts are into blending their desktop OS and their mobile OS. OS X icons and UI elements are influenced by iOS.
My proposition is to avoid to recreate the current look and feel of OS X but to capture the general direction of latest mobile device elements, such as:
- shadeless pastel colours
- web-font icons
- sans-serif fonts
- navigation system that breaks the historical scroll down approach
I would not stick to specific iOS or OS X solutions but I would blend between Android and iOS. Windows OS is still going through turbulent changes and we should wait for Win 10 to stabilise before bring him into the blending schema.
Although blending styles means apply some democracy to your design approach, do not forget that you will be the first client and consumer of your interface. Forget about listening everyone advice (mine included), be a tyrant in your first approach and then soften up and adapt to the reactions of your pears.
If you start listening to too many inputs in front of a white canvas you risk to collect to many capricious point of views.