This site is probably going to be useful before my next trip: One Bag is Doug Dyment‘s advice on how to travel with just a carry-on bag (or just a small bag, in case you’re not going by plane) and what and how to pack. His site contains an annotated packing list. Dyment’s tips are useful even if one doesn’t want to pack quite so radically minimalistic as he does.
And for the even more minimalistic travelers Dyment links to Anders Ansar who challenges himself by taking zero bags on his trips, though he cheats somewhat by having big pockets sewn into his trousers.