"No problem" certainly is different from "you're welcome," but to me it has a certain charm.

It's similar to "don't mention it" or "not at all," both of which are old-fashioned and a bit formal. It's also similar to "de nada" in Spanish.

What I find unnerving, though I know it's regional and certainly not meant to offend, is "yep" in lieu of "you're welcome."

Of course, I can't walk my dog without overhearing the F word about ten times, so it doesn't take much to charm me.