If ever your searching for 3D models cars and trees for your exterior architectural renderings or for furniture and appliances for your interior renderings, I suggest you visit these sites they have a wide array of free 3d models.
http://archive3d.net/ - a large archive 3D models. Models are categorized according to type and brand.
http://www.archibase.net/ - a large archive 3D models. Models are categorized according to type and brand.
http://www.3dxtras.com - limited to 15 downloads per member
http://www.fritzhansen.com/chairs - a furniture company which offer free 3d models of their products
http://gfx-3d-model.blogspot.com/ - I visited his blog and I really found a lot of good quality models in this blog. I really like his cars and architecture collections.