The "best rifle/pistol whatever" might better be stated as "what's the best firearm?"

If this is what your asking, then my answer is the almighty Remington 870 Express Super Magnum with a variety of chokes.

Very versatile and could be the solution to the majority of hypothetical shooting situations the average person thinks of.

But they are sooooo many "best firearms" out there, AR's, AK's, Glocks, 1911's, Shotties, etc.

One could also argue the "best firearm" is the one being held by a well-oiled bikini chick with your name tattoed enscribed on her beach towel.

Man did you open a can of worms....best firearm though, definately the Rem 870.  Everyone should own one.  Well, not everyone.