We used epoxy grout (same as the granite counter tops). Its expensive - it took 4 "kits" at $20 each for $80 - but it is worth it. Having a fully stain-proof backsplash is a good long-term investment.I don't really enjoy working with this stuff, since it sets up pretty fast with no way to wet it back down. The kits make a small amount, so it's doable. If you have not grouted before, I would not recommend starting with this. But if you do have experience, give it a shot. I would not do a kitchen area with anything else. Also, clean-up is pretty easy.
Here are some additional pictures...




We will seal all of this tomorrow and call it done. Was it worth all the effort? Yes.
















Here is end of the kitchen shot:










