What are some good examples of an eerie (or not) memory flashback (or flashforward)?
Hitchcock flicks are full of them, like this one from Spellbound designed by Salvador Dali.
All of the movie Memento.
The new Nightmare on Elm Street did a wonderful job of transporting a listener from a dream into reality, back to a dream, etc.
The Ring had some good eerie flashbacks.
I like the Gladiator flashbacks and flashforwards of him going to heaven and seeing his family again.
Lord of the Rings - Return of the King - the whole intro scene and fight between pre-Smeagol and the other hobbit.
Didn't Apocalypse Now have some great scenes of this nature?
Google is your friend:
The General's Daughter
I Am Legend
In Shane Meadow's Dead Man's Shoes there are a lot of memory flashbacks. They play a pivotal role in the film and are realised by using grainy black and white for the visuals and a very subtle HPF, some reverberation and a bit of delay for the audio. Very simple, yet very effective.