A great tip submitted by Richard C. Haber: Non-supported webcams! Macs are definitely not the best at supporting third-party USB webcams. Many new macs include the built-in iSight, but for older Macs, or even for Mac Mini or Mac Pro users, a third-party USB webcam is still one of the cheapest options. A developer created an awesome driver that adds support for many third-party USB one. There is an extensive list of supported webcam. It makes it much easier to shop for a webcam for a Mac. Download the driver here on the developer's site. Thanks Richard for the tip!