One of the easiest and friendly service to use for your custom made models
Go to Site
One of the biggest resource market for buying / selling models, textures, materials
One of the biggest resource for 3DS Max Plugins
CertiPort is organization that do certifications for different software such as Autodesk 3DS Max, AutoCAD or Adobe PhotoShop
You can follow their tweets @certiport
One of the biggest resource for 3DS Max Scripts
3D Printing Community with shareable 3D models and tips for 3D Prints