Good job man! Very nice space, i like the lighting those windows give.
You can try chamfering the sharp edges of the objects like the book shelves, the walls, etc ... to get better highlights.
I feel like the sofa needs some type of leather bump.

it'll look much better.
Also the mapping from the wooden structure could be better, the books are perfect tough
keep it up.
Antec 300 Casing/Windows 7 ultimate 64/i7 920/ ASUS p6T/ 6GB RAM/ Sparkle GTX470 1.2GB & Asus GeForce 8800GTs 512mb