Go with granite. Marble will be too much maintenance.

What about using quartzite? It is a natural stone but is more stain resistant than granite or marble. And it looks amazing!

Quartzite is the best, but pretty pricey for a bathroom countertop.

Perhaps look for a remnant.

if you go with quartzite, keep in mind that some places classify it as a granite, some as a marble. it's not standard, and if the people you talk to don't know the difference between granite and quartzite, i wouldn't buy there.

quartzite's a weird hybrid. it looks like marble a lot of times, but it's hard like granite.

marble is generally ok in a bath, as long as you take care of it. you have to be careful with acidic things on marble.

Marble is porous and will stain or etch with acidic materials. If you like the marble look try a marble look quartzite product. Also check with fabricators and see if they have remnants. It will be cheaper and for the average bathroom the remnants should be large enough.