Stephen King's novels tend to be a bit long winded but his short stories are usually quite good. The older collections tend to be better- Night Shift, Skeleton Crew. Plus they work for a rather popular audience.
I would go with Poe. If you want to memorize some of his poems, perhap that might work.
Lovecraft is better for reading than retelling. I am a fan, but the language is kind of awkward and heavy. THe modern Cthulhu stories have generally not ba been impressive, with a few exceptions.
(oh, if you are interested in some fan fiction- check out this-
http://www.callofcthulhu.org.uk/viewforum.php?f=142 )
Richard Matheson is pretty good too.
For one of the best collections of short horror- at least through the 1980s, check out
The Dark Descent. Some classics in there- Faulkner, Hawthorne, Lovecraft, and some more modern stuff as well. One story, I think it was Basil Cooper's Shaft Number 247 in Cthulhu 2000 was really quite good.
You might want to check out Clive Barker's Book of Blood, although I was generally unimpressed. I have liked some of his long stuff, but this didn't work.
One of the problems with horror has been that its a fringe genre. Because its often considered "low brow" it also attracts writers who are interested in "alternative" issues. I got no problems with that usually, but sometimes it goes a little over the rails. The line between vampire horror and vampire romance, for instance, has screwed up the
genre.
I have recently pickup up THomas Ligotti, based on a recommendation from a friend. Anyone read his stuff and care to comment?