Bookshelf Ideas

As a Christmas gift to myself, I'm building a bookshelf!

I've been in a studio-type apartment for over a year and most of my things are still on the floor. My books are scattered everywhere so I thought it's probably time that I do some re-designing. I looked for ideas online on some of the cutest and space-saving bookshelf interiors.

Below are my favorites.

A tree-style bookshelf! It looks so cute. And witty.

World Map Bookshelf!
I want this but it seems complicated.

Under the stairs/bed bookshelf.
This looks the most workable and convenient for my room.

I'm not yet sure which design I'll pull off. I have a friend who's amazing in carpentry and he promised to help me. I seriously cannot wait.