I agree totally with dsk.
I carry a Glock 19 every day, and also own a Custom Novak Hi-Power(built by Kurt Wickmann) and used to own a custom 1911 Commander carry gun built on an SVI platform. My first handgun was an HK P7M13. I much prefer having a sweep-down frame-mounted safety, or squeeze-cock safety on my gun. Those two specific types of manual safeties are both extremely fast and natural to disengage, and become totally subconcious with a little practice.
I, as well as many armed professionals who are far more capable and accomplished with a pistol than myself, have expressed the desire for a 1911 sweep down safety on our Glocks. This would do two things. First, it would make holstering and quick-drawing the gun much more safe for the operator. Also, it would act as a buffer in case your gun gets grabbed or taken from you in a struggle. It's been shown that it takes most people who are unfamiliar with the 1911's safety at least 30 seconds to figure out how to make the gun ready to fire. As it stands now, if your Glock gets grabbed, you're probably toast. If I ever get into a hand-to-hand fight while I ever have my gun on me, I'd rather have that extra element of safety, just in case my gun falls out or gets taken from me. And by the way, the HK P7 DOES have a manual safety. That's what the squeeze-cocker is. This is why most people survive getting their P7 taken from them in struggles. The dumb perps can't figure the system out quickly enough to use it against the owner.
I love my Glock 19, and carry it daily. Do I view it as a "safe gun"? Let me put it this way. I never worry about it going off by itself. I do however worry about it being used against me if I ever screw up in a fight, because it has no proprietary aspects whatsoever. In other words, it's a great gun, there's just no room for error with it. None at all.
If Glock were ever to make a Glock 19 with a 1911 style manual safety, I would RUN, not walk, to a dealer to snatch one up as soon as humanly possible.