In addition to adding a blogroll (which I have been remiss with) – I added a list of vendors that I use on the sidebar.
I can’t say that these are the best or the cheapest – but that I’ve been using them for years now and have been very happy with the service and products.
Uline (for packaging supplies) is amazingly fast. Usually next day service.
ShadesOfPaper (just great to work with). Again, I usually get next day delivery from them (located in New Jersey).
Dickblick has just about everything I need for archival matting. They are only missing one pre-cut mat size (16×20 opening on 20×24 mat). I usually get that from Stu-Art.com
And of course there are the usual suspects for my infrared stuff; and I don’t think you really need to mention B&H to a photographer.