Unfortunately I haven't found any good heirs to the throne lately for the horror genre. maybe cause it gets broken up into other genres more so than SF/Fantasy does.
I'd like to second the votes for Stephen King ('natch) and Simon Clark. Stephen King seems to go for new things and is pretty giving when it comes to rights to his short stories. I'd love to hear 'Survivor Type' done by an actor that could pull it off.
I'd also suggest Bentley Little (who is the best horror writer going right now and my vote for 'heir to the throne'). Several of his stories in The Collection would make crackerjack Pseudopod eps.
Other living writers that would be great would be Joe Lansdale (Check out High Cotton, Bumper Crop, Writers Of The Purple Rage or By Bizarre Hands for some great, great short horror), Ramsey Campbell (can't speak for his novels which are pretty slow, but he has some really good short stories), Peter Straub, Douglas Clegg, Rick Hautala and Robert McCammon.
Also, Leisure Books has been putting out work from all sorts of 'just below the mainstream' horror writers from The U.K. and the U.S. You know some of those guys have to be sitting on short stories that they would be happy to have available.