The ol' drop leg rig. I have one that used for open carry while riding my motorcycle (I had a crotch rocket). It works great for that, but they suck for anything else. It's nice that you can get to your sidearm from nearly any position, but it's not comfortable. They walk with you. By that, I mean that they swing front to back. The only way to stop this is to tighten to the point that its uncomfortable.
Plus they just scream for attention. More than 3/4 of the people I run into while OCing don't notice. When I used my drop leg rig, people noticed from a mile away.
Unless you need it for a special purpose, I wouldn't recommend it. I'm actually getting ready to sell mine. There are so many other options out there. You can get a really good leather holster that rides somewhat low, but it's still on your belt, for a decent price.
Basic Gun Safety by Jeff Cooper:
1) All guns are always loaded
2) Never let the muzzle cover anything you aren't willing to destroy
3) Keep your finger off the trigger until your sights are on the target
4) Be sure of your target and what is beyond it
