Mike, whether you're an outdoorsman at risk of falling butt over teakettle, or a cop, or a CCW holder or simply keep the gun for home defense, the weapon being dropped with a round in the chamber is a real possibility. Colt recognized the need for a locked firing pin at least twice over, first by creating the Series '80 with internal, passive firing pin lock, and second with a bright-colored tag on the first "re-issued Series '70 pistols" warning that they could go off if dropped with a round in the chamber.
That kinda settles it for me, and all the Colt 1911s in my carry rotation are Series '80 with the parts in place. It doesn't get in the way of good shooting; I've been able to win matches with them.
If you prefer the Series '70, I'd strongly suggest installation of a lightweight firing pin and a heavy duty firing pin spring to minimize the chance of an "inertia discharge" if the pistol is dropped or struck.