What exactly are "regular coax connectors"? Do you mean "F" connectors like you see on CATV equipment? "UHF" connectors like you see on ham radio gear? "TNC"s like mobile phones use? "N" connectors like satellite TV and test equipment use? "RCA" plugs ala cheap consumer video equipment?
BNC's are pretty much the standard for CCTV and datacom stuff. Nice constant impedance, easy to mate/demate, and even somewhat weather-resistant when mated. Widely available, in crimp-on (recommended), solder clamp, and twist-on (avoid these) versions.
I guess you could use different connectors for video, but you will need adapters to connect to the cameras, monitors, switchers, etc., which will all have BNCs on them. By the time you buy the adapters, you might as well have used the proper plugs to begin with. If you use some kind of non-standard connector, whoever is working on the system after you will be cursing you under their breath when they have to change something out in the future.
Whatever you use, you will need a connector and cable with a 75 ohm impedance, in order to get a decent picture with minimum distortion.
[This message has been edited by NJwirenut (edited 03-19-2002).]