PLUGINS
Flay.com
Flay is THE source for plugins, boasting the most extensive database of plugins and tools available for LightWave.

MODELS & TEXTURES
3D Cafe
3D Cafe has been online for a long time. It has a nice library of free textures, images and models.
Preset Central
Awesome site containing hundreds of LightWave presets textures, images, models and scenes for download.
Luxology
Luxology, a small company run by Ex-Newtek employees and developers also offers a login section with presets, tutorials and other LightWave related stuff.