action setup is a subjective issue. i see it as a personal preferance as opposed to the existence of an ideal action. if you play clean + single coils, it helps if have a relatively high action. this will improve single note definition & sustain. for those who shred, they prefer very low action, so low that once the strings are picked, it'll rattle against the fret wire & buzz. technically, this ain't string buzz, it's an eliptical phenomenon due to a lowered action. true fret buzz will occur even if you have high action.
my action is pretty low- 2mm (bass side) & 1.5mm (treble), measured @ the 12th fret. i love to play fast & this is an ideal personal action to help me concentrate on my playing without inducing lethargy, which will result in mistakes. FYI, i'm using a set of .009s. only my PRS has a slightly higher action (2.5mm bass + slightly >1.5mm treble)as i have a a slightly thicker set there- .0095s
this low action is also suitable for Black Metal stuff. i pedal bass notes & it helps to have low action.
i talked to Paul Gilbert once (during his clinic) he has super low action on his guitars & they rattle even when he doesn't pick hard. i asked if he can live with such annoyance & his reply was that the very low action helps his playing. it's ok as long as it doesn't come through the amp. i have embraced this philosophy ever since.
whoa... talked too much already. hope this helps!
