I installed the backsplash just above the lip on the countertop, so there should be no problem replacing the counter top. I may need to add to my backsplash if I decide not to go with a backsplash on my new counter top.

i really like the calcutta marble look, but may be too busy with my back splash..

Yeah, I'd keep it simple with that backsplash -- a white or a (contrasting) gray, maybe quartz or solid surface, seems your best bet. No mini-backsplash of counter material, if you have the backsplash tile available to fill in.

Have you looked at the Cambria counters and there are other brands that come in light grays and almost entirely white. These are quartz. Several would work with your backsplash.

Whitehall by Cambria

A white or a black might look like a near miss if the color tone isn't the same as the backsplash, so a gray might be safer and blend, only thing is I'd suggest it contrast with the gray of your cabinets so maybe a darker gray? With that backsplash I think you need to keep counter simple. Agree with acm re no 4" backsplash if possible, instead fill in with the same backsplash if you have enough.

You can get samples of all the different counters you're considering, and then look at them on site to be sure they match the colors of finishes you already have. I wouldn't avoid a whole category for fear of a mismatch, but don't assume they'll play well until you see it for yourself.