Mine came to me with 32" BFGs, stock Rubicon rims and stock suspension. The tires rub on sharp turns and do occasionally hit the wheel wells on the trails. For what I do, I can't really say its a problem that needs immediate attention. 33's would likely be annoying without a lift.
It all depends on what you do with the Jeep. biffgnar is correct, assuming that you often make full use of your articulation. If you don't, like most people, then you will have fewer issues with larger tires.
Functionality aside, I will also admit that I do like the look of big tires stuffed into the wheel wells at stock height. However, I also like things that work properly.