1/2 " stone tips look nice in a very light stone color

I love glass as a splash back. So easy to clean. A great way to add colour. Note that glass has a very slight green tinge unless you get ultra clear. So i would ask for a test sample for painted glass.
With some liquid chalk and help from good ol' google, inspirational messages are always present feature on ours. Also great for family reminders.

I think that 3" x 6" subway tiles are timeless. I'd suggest going to a real tile store to browse. If you have a piece of your granite to take with you, all the better. Generally they will let you borrow some tiles for a couple of days. In addition to white, you can also get in off-white as well as colors including black! Your kitchen looks traditional ( a good thing if you don't want to be renovating every 5-10 years!). Another option to personalize your space is to opt for a colored grout.....maybe the color of your floor to tie all together. Btw... There is now a pre-mixed grout that is stain proof as well..nice!

I'd stay away from the tumbled marble look as it is sooooo generic and a bit boring.