Bearded Dragon tank help?

I have finally saved enough money to buy a completely different set for my baby! (its not a baby bearded dragon its a adult but its my baby XD) We have been through the process of rebuilding our home and had to move to a apartment and move back in. Now that we are settled i raised money for a new set up. I was wondering whether i should get a tall 40 gal. cage or a wide 40 gal. cage. If its tall then its not going to be a tank its going to have walls with screens like a window screen or sliding door screen. (not the sizes) if its wider than it is tall then its going to be a normal tank structure. Anyways im going to get gvine (that wooden stuff) and place it in the "hot spot" i also want some rocks too. Im also wanting to get some sort of platform that can stand sturdy but also sag a little almost like a hammock but its not, and a hide out. Now i haven't been paying much attention to him lately and that makes me sad so i want to give him a luxurious home to live in for the rest of his life! now i have the money. I just need more suggestions. So more height or more width? Any more ideas on the interior? and 1 more question. I want to let him run around but i don't a have room specially made for him so how could i make my room just one big open play area? please help!