I still have one of the early Chromebooks, the Samsung 5 550, and wanted to improve the webcam. After some research, I bought a C920 webcam from Logitech. Stuck the C920 into the Chromebook's USB port and fired up Hangouts to only observe that the Chromebook still uses the internal camera. After a brief look on Google, I found out that one has to go to chrome://settings/content and change the camera to the external C920. I followed the directions and the C920 worked in the Camera app but every time I started up Hangouts, the Chromebook reverted back to the internal camera. So I cleared my Chrome cache, and the right camera finally worked in Google Hangouts. The C920 quality is immensely better than the internal camera however the CPU on the Samsung 5 550 Chromebook is not fast enough to do high definition (HD) videos. Regardless the lack of HD, I'd still have to say that the C920 video quality is immensely better than before so it was still worth getting it.
Delving into surreal worlds...