A plain White Marble plaster is easy on the feet and should last for many years if you keep the pH and alkalinity at the proper levels. You could step up to a polished quartz product, which is more durable. If you can afford it, then Pebble Sheen by Pebble Tec is excellent. Wet Edge also offers a Satin Matrix product that would fit the bill.

I'd like to add that you have to pay attention to the calcium (and other minerals?) as well. I've always been really conscientious about the chlorine and ph, but lazier about bringing in my water to be tested for the other stuff. Over time my plaster has become really rough and I've got to redo it now.