Places to visit, hotels to stay at on trip visiting national parks in Southwest?

My wife and I and another couple are planning a trip starting in Phoneix, driving up to Zion National Park in Utah, through Las Vegas, and then back into Phoenix. We’re all outdoors people and have done “the strip” in Vegas. Anyone out there who can recommend places to visit (national parks, interesting sites), great restaurants (can be either fancy or down-to-earth folksky), and any interesting places to stay? I would love to hear what the folks out in the community can recommend.
We are planning to go around Memorial Day weekend for probably no more than a total of 6 days.

You can go to Zion, Bryce Canyon, Canyonlands, Arches National Park, Antelope Canyon, Rainbow Bridge, and end in the Grand Canyon. Take a Road Atlas to get the route, you will enjoy this tour for sure. You will have enough time to visit one a day, and drive to sleep in the next city (nearest to the next National Park). Here http://www.ytbtravel.com/pcflo43 you can find hotel rates, video tours inside the hotels, locations, maps, etc. You can book on line. You can also rent a car or flight tickets in this site… I don’t know where you live. To know about the National Parks go to http://www.nps.gov/ it will be very helpful. The parks and places I selected are a MUST SEE. Enjoy!!!