Agree with Poseanne about Mission Ridge, and jhcooley about Whitewater. Tony mentioned Brundage, which has a terrain expansion planned that will add to the off-piste advanced/expert terrain, but yeah, with its relatively low skier visits feels like a small mountain. One of my favorite places I've skied. Great snow, glades everywhere, empty wide open groomers. Forget I said anything, just now. Nothing to see here folks, move along.
Beaver Mt. Utah is another fun place.