Some goodies in here. I have a hard time placing PSYCHO next to "Ed Gein" except the book's author was reading about Gein and his mummification lore But I could never doubt the strength of that film - no matter what context.
DIRTY HARRY's origin goes back to
THE SNIPER (1952 d-Ed.Dmytryk) with Arthur Franz as a desperate-to-be-punished hater-of-women rifle killer in SF, on the same roofs, etc. THE SNIPER vs. DIRTY HARRY is interesting because HARRY is almost a page-for-page rebuttal against the script of SNIPER (as opposed to a mere Remake). SNIPER's not a great film, but I have enjoyed it far more when seen in its relationship to Clint Eastwood's work.
10 RILLINGTON is pretty chilling in its, well, "nothingness". The absolute lack of emotional intensities, even the impact of murders in that neighborhood are 'stiff upper-lipped'. Such nonchalance, such a low impact is portrayed by everyone. But no one's really sure IF killings are going on or just 'tragic accidents' either.
As for IN COLD BLOOD. The book and movie are powerful in their own ways. Seeing the film on the big-screen should be a Must-Do by any film-lover. That ending is awesome, on the big screen. The book - for whatever weaknesses and prejudices that Capote incorporates - is a great read, too. I probably saw the film first, but the book was read a decade later and I can flip back and forth without detracting from either. (It's hard NOT to see the actors "in" the book - that's perhaps the only 'weakness' but since those characters aren't walking around now anyway, it doesn't make much difference. I still know I'd never want to go to dinner with Robert Blake - he might claim to have 'forgotten something' and leave.)
There are two films on Jim Jones-Guyana and I have a hard time remembering which is which - one has Stuart Whitman and that's more readily available on DVD, but I keep 'seeing' Powers Boothe in his film version, but I don't recall anything else about his film than him.
One of the, well, "most fun" films I've seen about the Manson Murders is
THE SIX DEGREES OF HELTER SKELTER (2009, d-Dorsey). This is really an hour-long 'travelog' tour of the various locations AND discussions of the links to all the "just missed targets" and others involved. The first 10 minutes of this documentary are NOT promising, by the way - I almost clicked it off. But after that, the director-writer-narrator picks it up and connections are made. Like, Manson chose the LaBianca house because he'd partied at the neighbor's house a year and a half before, and his party hosts complained that the neighbors didn't like the late-night noise. So Manson went to those neighbor's house to pay them back. Except... the complaining neighbors moved out and sold the house to the LaBiancas, who were relative newbies to the neighborhood. Welcome to the neighborhood!