3D Modelling sites:

Renderosity

Community / store and freebies

3D Commune

Community / store and freebies

Daz

Models store & home of Vicky models

Runtime DNA

Community / store and freebies

VISTA

Birds and animal models store

Kozaburo

Fantastic free hair models

Bbay

General model store / military uniforms

Textures for 2D or 3D art:

LEMOG

A vast collection of free texture files

Texture World

A vast collection of commercial textures

Card Modelling:

Alternaterealms

Excellent card building kits for wargames

Design Software

Suitable for card model design

Serif UK

DRAWPLUS (which I use)

Free paper models

Space Station 4

Lots and lots of free models

Iceberg

Lots and lots of free models

Japanese model site ?

Lots and lots of wonderful models