I know it's probably the most frequently asked question... but I'd love some help with my backsplash!

I have Formica cabinet doors, a light gray pattern on the bottom and white gloss on the uppers with a few stainless steel/frosted glass cabinets between the windows. Paint is Stonington Gray. Appliances are stainless steel. Counters are black forest granite. Floor is gray 12x24 tile (picture attached). It's a long galley kitchen, sorry no pictures of the whole thing.

I want to introduce some color into it. The adjoining room is painted in the same gray with orange accents and gray-and-orange carpet. At first I wanted to do orange but now I'm thinking it'll be too much.

Here's what I'm thinking: a simple backsplash so as not to compete with the granite, maybe a gray subway tile or a subtle gray glass mosaic. But I want to put a stripe of some color into it, like a pretty blue or green that won't fight the orange in the next room.

Please help! What do you experts think would look best? I'm planning on going to the tile store tomorrow so I'd like to have an idea of what I want so I don't get too overwhelmed.

Thank you!