I'm hoping some of the pro's will chime in, but I wouldn't do travertine. It tends to look pink. Have you brought any samples home to test in your space? Your counters are warmer in color and your walls appear cooler. The marble seemed ok to me, but I would get a sheet and bring it home. Take pics and post them.

Subway all the way!

The only thing I see going with the counter and your paint color is a white tile.

I agree the wall color does not complement the granite.

Yes for sure repaint, the blue is too cool for the warmer more traditional items in your kitchen. There are a ton of back splash possibilities out there these days, and for sure bring samples home as they can look so different in your home than in the showroom! Some glass tiles tend to be modern, there are some that are not because they are mixed with more traditional materials. I would be careful if you are considering selecting glasstile, maybe you and your husband can find something else that both of you really like! You have a great start there, you are so close to having it look great! Good luck!

following...

A nice subway tile in cream and repainting in a color that goes more with your kitchen would be lovely.

this is the marble you picked w/theVenetian (it's a different shape, same stone) . has a tendency to look pink. I'd pass on that one.

all of these pics are w/Venetian Gold

regular travertine

tiles. you have to be sure to get the Ivory travertine.

you could do a matte off white subway in a herringbone. you nice long countertop would be a perfect display for this

glass linear bar mosaics in a solid color. this one is a bit more modern. but looks nice

here's your small bar mosaics you have in your post example

Paint the walls please. Simple soft white ceramic subway for your splash. If you wanted a warmer palette ......gold to off white? Wall color is big boo hoo.

Thanks for the advice. I have decided on an off-white glass subway tile. I will post pictures after we get it up!