I remember Aliens 3 overdoing it with f-bombs in the theater.
The audience I saw it with just just found that hilarious - especially after the governor gets dragged up into the ceiling.
Die Hard 4.0... It's weird, because you need to have yippe-ki-ay motherfucker in it, as in the DVD, but the PG-13's version of some earlier lines is actually funnier- To wit:
Theatrical Cut: I'm gonna go, get my daughter back, kill everybody else
DVD: I'm gonna go, get my daughter back, kill those motherfuckers.
It's something about the expression on Bruce's face and the delivery of the line - his tone of voice - that makes "everybody else" far superior, cos it does somewhat imply a lack of concern for any innocents, or at least a knowing assumption that in a movie like this, everybody there will be bad guys.
Thing is, swearwords are a tool and a weapon - nothing wrong with them when used properly, but overuse deprives them of their power. But censoring them - especially by meaningless phrases (why can't they think of something that fits the scene) is always wrong, and beeps are always wrong*
*- there are two exceptions to this rule, though both were intended for the beeps to be heard rather than the words: The Goodies punk episode, and the Father Ted Eurovision episode. Neither of which would be anything like as hysterical if the beeps weren't there.