"It's the twenty-first century, MC's please,
you're killin' hip hop
when you
sample the Beegees."
I think it depends on what song is being sampled and in what context. I have no problem with MC Chris sampling Vanilla Ice's "Ninja Rap" in "Bad(dd) Runner." Or MC Lars sampling Brand New's "Okay I Believe You But My Tommygun Don't" in "Mr. Raven." There are some songs, though, where it's just unacceptable. Lil John sampling Ozzy's "Crazy Train," for example, was awful.