Pretty much what everyone else said, though I'd suggest that you check out Kages as well. Their enclosures are a bit pricier than AP's, but this includes shipping and a fast turn around time. I ordered one of the base model 4'x2'x2's off their website in November and FedEx delievered the enclosure one week later -- they are that fast!
Standard enclosures are 1/2" PVC with sliding polycarbonate doors and (should you want one) a 10"x10" belly heat recess. Enclosures are shipped flat like most others and assembly is required, but it's very easy and straightforward -- step-by-step instructions are included, pieces are clearly labeled, and holes are pre-drilled. The enclosures are pretty high quality in my opinion, and only the few AP enclosures I've seen have them beat on this front. The only real downside to these enclosures is that you need a stacking kit to stack and they don't recommend stacking enclosures over 4'x2'x2'.
Whoever you go with, I recommend getting a 4'x2'x2' for a male royal. They'll use all that space as long as they feel secure. Happy cage hunting!