Mansion Rooftop

So the new wooden planks made me want to finish up my house. Here's how the rooftop turned out. Looks empty, do you guys have any suggestions on what should I do with it? No, not going to use it has a storage room :p I was thinking of a greenhouse or indoor animal farm, but maybe someone can suggest something more creative. Not completely done, still going to add more windows on the side and stuff.

It won't let me upload the schematic, it says

Upload Problem:

• (schematic) - File extension not supported
  

Anyway, I need suggestions for what to add :) The floors below it have grass flooring, If anyone has ideas on how to caroet it, I'd like to hear them :)

Additional Notes

The seed I built this on was amazing. I put up a page for it: http://www.planetminecraft.com/project/amazing-seed4-diamonds-and-stronghold-near-spawn/