Chambered safety on. The couple times I got nervous about a situation, I reached down and flipped the safety off.
I would never carry unchambered, and I've been thinking about carrying safety off from now on. If you need your weapon, you are going to regret having to chamber around. Especially if it's a situation where the element of surprise would be beneficial.
The very atmosphere of firearms anywhere and everywhere restrains evil interference. -George Washington