i find myself preferring C-sharp major to D-flat major—it feels like a quite different key, & a brighter one (entirely a different "colour"—d-flat major is a pale blue like the edges of the sky, c-sharp major is a more brilliant and intense shade of gold than what i think of as the "golden key" b-flat major)
i also quite like e-flat minor (which is, again, the polar opposite of d-sharp minor—deep purple as opposed to pale green)
with equal temperament there is no acoustic difference between enharmonic keys, so this is, i suppose, a weird psychological phenomenon, probably brought on by years of reading/playing music and enharmonic keys looking quite different on the page
The concept of key-colour is very well established, and not nearly as random as you suggest.
Ah, yes - synasthæsia; the two fundamental problems here, however, are that (a) not all listeners and musicians posses - or are conscious of possessing - this faculty and (b) those who do possess it do not all make the same colour/sound relationships.
indeed. i first became aware of synaesthesia when talking to someone else with the same ability, who described b-flat as red. my immediate reaction was "what? it's not that colour at all! maybe you're thinking of A major" >.>
gradually it became clear to me that not everyone gets colours & textures from keys, and what they do get is entirely individual as well
