who's hating on the neptunes cause they rip something can hate on almost any urban producer the last 20 years, they did all rip a lot, sometimes they paid copyrights, sometimes they did
how do you think oldskool producers like grand master flash, africa bambaata, eric b, ... made their masterpiece; by sampling the big funk, disco, reggae & soul stuff and take their id's to make a new beat.
Dre, one of the biggest producers arround does almost nothing else. One of his recent hits, "rich girl" from gwen stephanie, is a pure rip off of Louie Lou's dancehallclassic, "if i was a rich girl", wich was also a twisted version of an old musicalsong. The only thing he changed is the second kick in the loop.
He did the same in his hole carreer. NWA's "Express Yourself"'s beat is the instrumental of the funkclassic "Express yourself" from charles wright with a slightly modifed drum pattern and some extra samples, ...
Even lil jon's yeah's main team the fake strings, comes from an english acid house classic from '88 you probally won't know.
and a second thought: making real original things isn't easy anymore, cause most things has already been done. It's in the variation and interpretation that you can find your own style.