Arducam $50 + Arduino incredible product coming out of DIY Drones
Cheap Thermocam Nice! Thermal imaging!
Universal Arduino Camera Shield cool board, completely DIY (gotta make it yourself)
Arduino Due should be able to ask as a USB Host and access a webcam can't find any examples though
Craft Camera this is a nice all-together camera built from arduino shields and add-ons. nothing new but the packaging.