The national parks are beautiful. You will also likely find the mountains in Salt Lake and Provo to be very beautiful. A short drive up Provo canyon provides stunning views such as Sundance ski resort and Bridal Veil Falls. You might enjoy a hike or even mountain biking down the mountain. You can ride the chair lift up and bike down.
I also recommend making time to visit Temple Square in Salt Lake City. The Salt Lake temple took forty years to build. There is a beautiful statue of Christ, incredible art, world's best choir if you can catch the Mormon Tabernacle Choir. Just ask for a tour and you will get first class treatment. It is a short drive from the airport. Park City is where the olympics were held and a fun tourist attraction located right in the mountains.
I really like all the red rocks in Southern Utah - Zions, Bryces National Park, and Arches in particular.
Enjoy your trip to Utah!