I am wondering what the typical setup is for photographers arriving at a photo shoot. How much equipment do people really bring for their typical bread and butter shoot? My concern is if I show up hauling a wagon load of gear up to the front door does that show professionalism, or will it immediately set the agent to tapping her wrist watch? Just because you can, should you?
Don't worry about "showing professionalism". You should just focus on getting great results in minimum time. But the fact is that you don't need to carry a wagon load of gear.
What you carry to a shoot depends somewhat on your style of shooting:
Wayne Capili, one of the best in this business (uses #3 above) and did a guest post back in September talking about the gear he uses. Wayne's kit is shown above. Click on the photo of Wayne's camera bag (Lowepro hard side 200) to read the details. Besides the very small case of gear, Wayne probably carries a tripod, light stand or two all of which one could carry under one arm with a shoulder bag. So just because you shoot with small flashes doesn't mean your need a lot of gear.