either one would work. I would make sure it complements the colors in the countertop.

Add some color! It will make your kitchen pop. I think the others might be a little too bland. Just my opinion.

color can always be added with accessories as well

I would use the glass tiles for some color.

Off white subway. The canisters will stand out much better with a white background.

I vote blue tiles. Cream/white would blend in too much with your cabinets. Grey tiles would also look nice.

I'm voting for the sea green glass tiles, also...I think that would give you more color and tie in your living room furniture since it's visible. Keep in mind, however, if you decide to redecorate with different colors in the living room (and it looks like that would be easy to do), your backsplash wouldn't match. Depends on how much you like to redo things, you might go with a neutral stone backsplash that looks good with your counters. This link has some pretty tiles. Glass Tiles

Definitely a contrasting color, even if subtle. Agree the grey tones in the countertop would be a good accent, natural stone or glass.