I've always thought it was somewhat odd to bother including fairly ordinary clothing in the equipment list. Along with things like bedrolls and lamp oil, it seems like something better left hand-waved. Unless it's somehow blatantly inappropriate to the character, I feel it's reasonable to just assume that he or she has enough pockets, wears boots and gloves while adventuring, is warm or cool enough in the local climate, and would look out-of-place at a high-society gathering. If they're going to disguise themselves as priests, visit the frozen tundra, or attend an aristocrat's wedding, then you pull out the shopping list with specialized clothes and GP values.
It also bugs me that the default clothing descriptions are so heavily medieval Europe-flavored. "Breeches"? Does anybody picture their characters wearing breeches?
That said, though, I think that describing characters' clothes is as necessary as describing the rest of their appearances. My current character, a human Wizard, has "artisan's outfit" listed on his character sheet, but when I actually describe it, I mention that he's wearing drab, slightly stained and badly worn laborer's clothes, mostly linen and leather, colored beige and brown. He's got a pair of heavy work boots, but if it's warm out, he's probably barefoot.
