It seems silly to create a new thread every time we find a new J Crew $20 off $80 coupon code, so I'll just keep adding them here.
STYLETREAT - Extra 30% Off Final Sale + 25% Off Full-Price (Exp. 10/31)
J. Crew Factory:
EXTRA25 - Extra 25% Off Everything (Exp. 10/28)
Don't forget to place your order on the "catalog phone" available in most J Crew b&m's to get free shipping too.