HP Webcam HD-3110 and the Motion subsystem. Both worked out of the box using the Raspberry Pi and the default (but upgraded to latest) NOOBS installation. Neither had an issue, and I was up and running with a security camera quickly. Another nice thing about Motion is that it exposes several external commands as a means to provide API exposure... so I can integrate a web application or send an e-mail at the start of an event. It would be great to send an e-mail whenever motion is detected, and send the video or photos related to the event.
Once the security camera was working and stable, I added back in the GPIO garage door opener remote that I hacked together. Working together, I now have a security system for the garage that can open and close the garage door from any vantage point. I deployed it up on a shelf, next to the windshield wiper fluid, where the webcam would have a nice perch.
I whipped together a quick Python script that would briefly engage the GPIO pin on the Raspberry Pi, so now I can sit at my laptop and watch the garage door go up and down. Ultimately I will place this feature behind a web application for ease of use. The Python support for Raspberry Pi seems to be a first-class citizen, so I might use Bottle to create a minimalist webapp for exposing the webcam feed and garage door controls.
I still need to build an enclosure... and perhaps upgrade the camera to one without an infrared filter and an array of IR LEDs. The web interface will be the next thing on the docket however.