Here are some more classics that I love (saw this got bumped back up to the top of the forum)...
These Ghoulish Things - Horror Hits for Halloween (2005) (a compilation of oldies)
Sheldon Allman - Sing Along With Drac (1960) (my favorite novelty-type album)
Arch Oboler's Drop Dead! An Exercise In Horror! (1962)
Vincent Price - A Graveyard of Ghost Tales (1974)
Troll Records - Thrillers And Chillers (1973)
Alsom some mixes available on the intarwebs:
Ghoul-Arama and Spook Party .. mixes by the guy at Scar Stuff
Mixes by alabamudclay such as "The Haunted Disc" and "Sounds From the Vault"
Halloween Hits 01-06 compiled by Dan Augustine
Vinnie Rattolle's Halloween Compilations
and you should try to track down WAKY Monster Marathon mp3s from 1964-1966. Wonderful stuff.
To these excellent suggestions I would add these 10:
Coven - Witchcraft Destroys Minds and Reaps Souls (late-60's Sabbath-esque hard rock with a "Race With the Devil" vibe)
At Home With the Munsters
Zacherle - Dinner with Drac (or any of his LPs)
Classic Scores from Hammer Horrors
Gene Moss - Dracula's Greatest Hits (halloweiner listed this I notice but didn't mention artist - great Jack Davis cover on this)
Glass Prism - Poe Through the Glass Prism (Poe poems, set to 50's psych-prog; better than the Alan Parsons "Tales of Mystery and Imagination" LP though that's worthwhile too)
The Haunted House - (Spooky Swing from the 30's and 40's)
The Munsters - (1964 garage-rock cash-in to the TV show - and quite good)
The HP Lovecraft Historical Society - A Very Scary Solstice/ A Shuggoth on the Roof
Monster Mash Sounds of Terror (best of the vintage sound-effects LPs)
John Carpenter - Halloween OST
The Dunwich Horror - read by David McCallum
Bookmarks