One name that regularly crops up in the list of accessories for boards is Adafruit Industries. The company was founded by Limor Fried, who is an electrical engineer and a strong open source advocate. She has built a company that, as well as selling add-ons for Raspberry Pi, Arduino and BeagleBoard, also sells a fantastic range of kits for hobbyists, including a load of wearable electronics. Prom Tiara with multiple LEDs, anyone?
Return of the hobbyist
This is not an exclusive listing; there are other boards, but these seem to be the leaders. When you look at the numbers, you can see a fantastic number of people getting themselves involved in hobbyist hacking (in the positive sense) of hardware and software. It is also clear that engineering professionals have embraced these boards, for fun at home (well, engineers are different), for use in skunk works projects, and as the basis for commercial production. The large communities that have developed around the boards provide both support and stimulation. Are we looking at the replacement to Radio Shack for the 21st century?