It seems to me that Logitech cameras are the best in terms of finding usable drivers. macam seems to support them very well and they don't make bad cameras. I use a Logitech Communicate STX with macam and iChatUSBCam and it works pretty well. It does have some video issue on occasion when it's situated strangely, but all in all, it's great, and it only costs around $35 to $40 (USD).