Come on Chicago!!!
Everyone will have their own favorite. Along with Uno/Due, I prefer Gino's (if you like a bit more sauce and cornmeal baked into the crust - yum!) and Giordano's if you prefer more cheese. Lou Malnati's is also good, but I don' think it's as authentic as the toppings are baked right into the pizza, but it's still considered a Chicago specialty. All of these places are close to Streeterville.
That's a can of worms with no consensus.
Uno's (who started it all in the 1940s) and has no relationship to the horrendous national chain of the same name. Due, it's sister restaurant situated kitty-corner from Unos. Pizanos. Lou Malnoti's. The recipes are similar and there are family connections between them.