Yes you'll be riding a bit of everything. I run an IRC VE 33. This is by no means an endorsement.(actually I don't change tires to ride Moab) and I'm too much of a spode to tell much of a difference.
You'll have to find a tire that likes sand, yet will hod up to riding slickrock, which if you've ridden it you know has better traction than pavement. If you ride LaSal Mtn at all you'll find loamy dirt and mud and rocks and rocks and rocks;)
If this is your first trip to Moab, remeber this is Mtn Bike central. They are thick around the area so PLEASE keep this in mind as we are in real jepordy of losing this great riding area. So be cool.
We went to Canyonlands area last year to do the 5 miles of hell and the tire of choice seemed to be a trials tire. Those that didn't have the trials tires, ran VERY low air pressure. I think they make a tire that is part trials and part moto but can't remember the brand. Good luck anyways,