Generally speaking, I am okay with the idea. In fact, I recently sold a handgun this very same way.
I, like you, felt initially hesitant about the idea. In order to assuage my concerns I did the following: met the potential buyer at a familiar location (in this case, outside of my local gun range), had a friend accompany me, had 2 "unofficial" printed documents which contained the date of sale, what I was selling, who I was selling it to, etc., along with a "disclaimer" acknowledging that upon sale, I was no longer responsible for how the weapon was to be used....this, of course, was signed by both myself and the buyer, along with my friend (as a witness to the transaction). Also, since I "met" this individual on a weapons forum, I saved all conversations between myself and this individual, regarding the sale.
In addition, I requested the buyer bring a printed copy of a current drivers license (for verification purposes) and insisted that this be further verified by showing me the actual license. I, in turn, showed him my license so he could verify that I was legit and old enough to sell such a weapon.
All of this information I still keep and will always keep. Official? Maybe not. Useful? Definitely.
Thing is, selling a gun this way [to a stranger] certainly brings up several concerns. But, I generally think that it can be safely done, given the necessary precautions. Outside of that, there is not much one can do other than to simply go through a recognized FFL dealer.
Would I always do a "face to face" transaction? Probably not. It really depends on the situation.
Keep in mind, this is only how I personally approach such situations; hence, it is not "law." Some of the suggestions here were simply mentioned to me by various individuals who happen to be in law enforcement.