This thread makes me a much bigger fan of BJ Penn, a natural lightweight who fights anyone regardless of weight class. And does fairly well with skill alone, going the distance with Machida at 205. And I'll put Henderson in that club too, since he could have always stayed at middle weight, but isn't afraid to take a heavyweight like Big Nog.
I understand the financial and career benefits of moving down in weight, but as a fan you don't have to respect it just because it's a good career move.
I respect fighters who move up in competition, not down.