For USPSA, the Blade-Tech Stingray with the DOH (Dropped and Offset Holster) is great. If you get sucked into IDPA someday, you can just pull the drop-and-offset
widget out, and have a regular belt holster. Bladetech and comp-tac mag carriers are both also good. Singles are much better than double mag carriers, although it costs more. Can space around belt loops, form to your body better, ...