Prototyping Materials

I am compiling a list of good sources for prototyping needs. I would appreciate your suggestions for stores or online sources of materials for various prototyping materials. Also what country, state, province you reside in would be helpful. I already have a full selection of rapid prototyping sources. I am looking for material sources particularly for lower fidelity models and mockups.

Extruded Polystyrene Foam (XPS), Polyurethane foam, plastic extruded shapes and sheets, paper, foamcore, glues, casting materials, wood,

Thanks for your time:)

Could you tell us where you are located to prevent getting a bunch of suggestions in locations you can’t access?

I am located in Canada, but I am actually interested in building a wider resource database for North America. That is why I am interested in where people go depending on their locations. As an example I used to go to TAP plastics when I lived in Palo Alto, but they do not have store except on the West Coast.

I appreciate your help and time