When it comes to chain pizza places, I prefer Round Table Pizza. They have a very good crust and a spicy sauce that doesn't just taste like tomato paste. There's also a chain in Vegas called 'Villa Pizza', they have a really good New York style pizza, and 'Rosati's', here in Vegas as well, has a really delicious Chicago style pizza.
As far as crap pizza goes, I prefer Little Caesar's.
Oh, and don't get me wrong, I'll totally eat Pizza Hut or Domino's if it's around. I'm not that much of a stingy freak. And I guess of the two, I prefer Domino's. I have a buddy who used to work at Pizza Hut and he told me the first thing they do is shoot a shot of grease all over the pan they cook it in.