Here in Greater Atlanta, by far granite is the most popular upgrade because there is so much supply now that pricing works for nearly any budget. Starting price is typically $35SF +
Splash? Subway tiles are strong (almost to the point Im seeing it so much I think this may be a really dated look in 20yrs rather than a classic one)... Glass tiles are hot. There is so many to choose from .. ones even with stone blends that work beautifully alone or as a deco liner/insert.
Mary you've got great advise from Becky Sue. I will add that we personally have Silestone and I love it. It's now antimicrobial too.
I think the new trendy thing is glass. But it is expensive.
If you can afford it, go with Silestone--no maintenance, no stains, can take hot pots, and can look like any stone that you like, or can be a solid color.
How about soapstone or concrete?