Just the camera with one lens, palmed in the hand or over the shoulder even. I have been suspecting this for a long time but have been paying more attention lately, and realized that I am too lazy to pull out the camera, and even more lazy to change lenses, even when I look at something and see a picture.
However when I have the camera in my hand, then I tend to use it. Go figure. This is not rocket science but still something to keep in mind.
This picture is a great exsample, I picked the M up with a 75lux in the morning on the way to breakfast, and stopped cold in my track for the scooter. It just glowed at me. M8 75mm LUX on Larchmont Blvd Los Angeles, on foot towards the cafe. - click on image to see large.
Taking things a bit further, Mike at TOP - The Online Photographer, posted a suggestion that the single best way of really improving ones photography would be to photograph with a Leica and one lens for a year. no changing lenses, one camera, and ONLY one type of film. Learn to use the basic toold and keep working them to the tune of at least 2 rolls a week. I agree 100%.
Click to read the ONE YEAR ONE CAMERA post.
Click to read his explanation the next day.
*Exception to the rule naturally is when I actually work with my camera on a job, in that case a camerabag is very handy and one often need lots of specialized gear to make a shot happen.