NAPP - The National Association of Photoshop Professionals
B & H - My favorite "toy store". From beginners to pros, camera, video, electronics...
Digital PhotographyReview - In-depth camera reviews and forums
Archival Methods - Archival quality page protectors, binders and supplies for storing photos and negatives.
American Printing and Envelope Company - They make photo mailers up to 17" x 22". They consist of an envelope with string closure and two pieces of cardboard. The corrugations in the two pieces of cardboard are at right angles to prevent bending in transit.