Hey Dood,
I definitely agree that "height is right" for non ducted /normal FM and TV band conditions Dx. I have done plenty of Dx from hill/ mountain tops, particularity on the V/UHF ham bands.
Ducted signals seem to be much less dependent on height, but a bit of height to get an open horizon couldn't hurt.Same thing on AM b'cast band or HF.
For broadcast Dx (LW or 530-1710) nothing beats the ocean, especially if working from ie MA to Africa or Europe . But even a partial saltwater path to the US seems to really help.
And obviously, man made noise is REALLY an issue . IMHO, quiet QTH's in forest, mountains or at seaside on ANY band (LW, MW or HF) using Amplitude Modulation make a BIG difference ,not mater what the the desired direction of reception is .
NQC