Hey thanks. Actually, the lighting I'm using is very simple. I have one point light for shadows and one directional light for general illumination. I will try your settings.

As you are helping me, I have a question... Why things that look good when closer, don't look that good when they are far. It's the case of the little gecko I put on the front wall. It looks much better in a close up.

Then, a second question. I wanted to render the tree in a separated layer. I did so, and exported the picture as targa (with an alpha channel) but then, in Photoshop I couldn't figure it out. How do you compose the tree and the rest?