Hi Biana, I also like the idea of two-tone kitchen cabinets. I like them in classic colors that won't look outdated. Make sure to use the darker of the two colors on your base cabinets so the room doesn't look top-heavy.

With that idea, I would keep the countertops and backsplash clean and simple so it does not compete with your two-tone kitchen design. If you're going to have white uppers, I think that white countertops and backsplash create a seamless eye-line up to the ceiling.

Here are a few photos I found: white and navy, white and wood, white and mocha, and white and grey. If you are concerned about it looking sterile, I would suggest the wood or mocha as your secondary color for the base cabinets since they are warmer tones. Hope this helps!

white and navy

white and wood

white and mocha

white and grey