CG Society: One of the top 3D artist hubs on the Internet. Has a huge forums area, top industry articles and more.
3D Total: Just a huge 3D resource site.
High End 3D: Yet another big 3d resource site with tutorials, downloads and more.
3D Links: Providing a truckload of 3d links covering a variety of topics.
3D Resources: Providing a nice selection of 3D resources.
Lugher3D: Offering free objects,
tutorials and other Maya resources.
Autodesk: The makers of Maya, 3DS Max, and more.
Maxon: The makers of Cinema 4D
Newtek: The makers of Lightwave