seems as it's all preference, I'll add a couple cents. I think I'm gonna start dirt jumping, downhilling, riding trials, and doing park in clips and riding flats for XC and commuting. Clips are only legal if your wearing spandex, anything else just let it all hang out, be a man and ride the flats.
ive seen riders who have clips stick their feet out in turns and then clip right back in at the end of the turn. in fact the cover of decline mag with bryn atkinson... his foot is unclipped in the turn.