Yes, I'm cheating like buggery by listing just a few classics of weird fiction that I would like to see given the big-screen treatment. Or even the small screen treatment, I'm not that fussed.
1. The House on the Borderland
Yes, William Hope Hodgson's proto-cosmic horror novel might need a bit of tweaking. But there's enough good stuff in there to permit a genuinely strange and wonderful movie to emerge, shaking its clotted wings. Modern effects would certainly not have problems giving us spiffing Swine Things, and the visionary passages would be splendid - if handled correctly. The Irish landscape plus period detail offers potential for rather lovely scenes at the beginning and end. And how many other films offer a director the chance to depict the end of the world, and more?
2. Nights of the Round Table
We all like a good portmanteau movie, and Margery Allingham's 1926 collection has enough cracking tales to fill up a good ninety minutes. The framing narrative is a club where members tell strange stories, so it's already a portmanteau setup. I would choose 'Vlasto's Doll', 'Robin's Rath', 'The Fifteenth Green', and 'Morag-of-the-Cave', but most of her stories are pretty darn good.
3. Count Magnus
4. Ancient Sorceries
Another short story, but Blackwood's tale offers great potential as the nucleus for an atmospheric tale of witchcraft in provincial France. Again, effects might offer rather wonderful cat-creatures, and the contrast between the 'dream town' that Vezin sees and the modern reality could be handled very effectively.