Hahah, I am the opposite I feel a hamburger is less junk food than Pizza. I tend to regret more eating pizza than a burger.
That said I like pizza more due the different combinations you can place on them. the ingredients and base sauce can really change the flavour and add a new spin to the good ol' dish.
Burgers are not without merit, specially the ones from small business or plain home made. I love'em. We used to buy some pretty cool packed burgers from a neighbour that were full of ingredients and I still miss. They weren't exactly healthy ingredients, haha, but it really tasted good.