It's got to be hard for small stores like Bead + Fiber to even exist anymore. Places such Jo-Ann Fabrics sell a lot of the crafting basics that one would need to make a simple bead or thread necklace, but when it comes to finding unique, one-of-a-kind materials, stores such as Bead + Fiber stand alone. For such a tiny space, they carry a dizzying variety of items that reveal the work of a careful, inspired buyer. I think I could find inspiration browsing bazaars and markets across the world! Just look at some of the goodies you can find.
They also offer instructional classes, and I'm thinking of signing up for one of their kumihomo classes, which teaches the Japanese art of braiding to make gorgeous, colorful cords like these:
(even though it will require the use of one of these looms... which kind of scare me)
I can't even count the hours I spent at Beadworks in Harvard Square in high school, and while 80% of the things I bought there sat (and still sit) in little plastic bags waiting for my attention, it was the kind of place where one could spend hours browsing and imagining. It's also a major bonus that they encourage their patrons to touch everything! Note: Beadworks now does business under Boston Bead Company, but they closed their store in Boston and are now only in Cambridge.
If you're looking to get crafty, may I also recommend The Pear Tree in Brookline, where you can also sometimes find beautiful jewelry.