Going to have to go with other but too bad it's such a far way away so wouldn't qualify for an easy option in this town. Top choice would be a small place in Fairview, MT called The Powder Keg. Spendy but so good. Second would be the pizza I made at home a few months ago. Don't have a picture of it but was a stuft crust pepperoni pizza and was awesome. As for local places my top pick is Pappa Murphys but of course you have to bake it. I prefer the crust and flavor of it over others. For already made probably Dominos.
I voted Papa John's as for any big name pizza places that deliver it is heads above the rest (Domino's, Hut, Caesars, etc).
Big names aside, the best pizza I can think of is a Pizza Corner pizza, from the actual restaurant in Valley City. Their frozen pizzas are great, but in the shop is completely different and tough to beat.
I've also had good pizza from Rhombus Guys and Dwayne's pizza in Fargo, and I can't recall one Italian place in St. Paul that had some good stuff
I like Papa Murphy's, but voted for Pizza Hut, I think the secret is the sugar added in the sauce and bread. I read that most companies secret additive in typical non "sweet" stuff is sugar which gives almost anything that indistinct delectable taste.