If you'll direct your eyes upward on the screen, there's actually already a thread about this very thing.
"Post pics of your cage (No Conversations, please!)" is the name, it's a sticky at the top. It is a lot of fun to browse through, I've gotten some really good ideas!
You'll also find the cage vs. aquarium sticky, which addresses concerns about aquariums as homes for rats, to answer the other part of your topic title.