What are the colours of your cabinets and flooring in the room?
It is the back splashes job to tie in the cabinetry with the countertop - while enhancing the flooring and not competing for attention (too much pattern on pattern). You could go more modern with a simple creamy yellow or charcoal glass, or push it more traditional with a bone coloured subway tile. Depending upon your cabinetry colour, I would enhance the granite keeping it simple. Pull your favorite colour from one of the many colours in the granite, this will help make it all work well together! I always pull an unexpected colour - one that isn't readily seen (like a cream, rust or chocolate) I'd go for the charcoal gray. Send pictures when your done...

Take your granite sample and your cabinetry finish sample to your local tile specialist - that's really the only way to make the best selection for your taste, style and budget.

I would go with a tumbled stone and incorporate some glass and metal tiles especially if you have stainless appliances