If your diet is otherwise good, then a pizza once or twice a month is not gonna push you over the edge. Enjoy life occassionally! It's the 'average' American couch spud that needs to nix the pizza twice a week on top of the Denny's Grandslam for breakfast and McD's for lunch with Baskin Robbins for dessert!
A little of what you crave does you good. Remember moderation above all else.
Or make your own pizza. I love my basil pesto/feta/sundried toms/olive/mushroom/bell pepper/onion pizzas with LOTS of garlic on a wholewheat base. So does everyone else. It's still high fat and high carb, but by using low salt feta and wholewheat crust I minimize some of the worst aspects of commercially prepared pizza (being high salt/sat fats/white flour).