Longboard Lounge I check this one out every day. Club devoted to longboarding. Its pretty active, and includes a longboarding picture post, chat, etc. A great online longboard shop. This shop has really nice images of the products, from multiple angles so you can really tell what the stuff is like.
Fluid boards are very nice.
I especially like the Red V and Feugo. The only place I know of that carries almost every brand of longboard equipment. Everyone has been very please with their service. Check out the Classic. Sector 9 Sector 9 is probably the best known company currently specializing in longboards.