I've been reading Knock-off Wood a lot lately, and they had these plans for a book rack. They're great for my girl's room for three reasons:

The books face straight out (so you can see 'em)
It sits flat to the wall (12"), so I can put it behind her door.
It's sturdy enough that she could climb it (not that she should)

Here's the finished product:

I deviated from the original plans in a few places:

No arches. I didn't want to cut them so I tell myself they didn't match her room anyway.
Routed outside edges and rails dress it up a bit
Taller shelves (15" instead of 12")
Notches for her chair rail & baseboards

I'm particularly happy with how the baseboards came out, but I sort of messed one thing up: when I routed the outside edges, I didn't stop at the baseboards. The round-over goes all the way to the floor. Whoops.

This was a great project. It took me 2 days of carpentry (with the assistance of a 5-year-old), plus a day of painting. I spent about $90 on materials & a few tools that made it go smoother. I'd recommend it of you have an unused wall in your place.