Almost all military and LE agencies require the use of the safety if the weapon has one. There is good reason for this; in case of a gun grab that safety will give you a little extra time to deploy a BUG or recover yours, or just open the range(get the hell out of there). I carry my 3914 with the safety on, with a round chambered, always.
My usual cary battery is a BHP and a 940, I carry the BHP with a round chambered, hammer cocked safety on, just like the 1911. When I think I might be in a gun grab situation or a crowd I put the BHP on half cock with the safety on. I can deploy it almost as fast as the 3914 or cocked and locked, but I figure that by the time a gun grabber might figure out how to get the BHP to go bang, he will have absorbed an attention getting number of rounds (all of them) from the 940.
I know that a citizen CCW does not have the same risk of a gun grab as a LEO, mainly because his presentation should be a really big suprise to the BG, but you can't be too careful. And remember if you are Joe CCW you do not have the back up of a cop, or the weapon retention or recovery trainiing an LEO usually gets(or should get). And you probably do not have a BUG. I therefore think that CCW folks should give consideration to carry with the safety on, it takes almost no time to flick it off during drawing the weapon, or you can keep it in the safe position till you need to fire. BTW, the magazine disconnect can be useful if you are going to lose your gun in a struggle, you can drop the mag, leaving the BG with a lightweight club.