Although my favorite rides are HM and Pirates.... I like to get Fantasyland done first, since Snow White and Small World are like a WDW warmup, and Pooh and Peter Pan are virtually impossible to get into later in the day. I work my way towards HM because its an excuse to keep pushing forward even though I want to pass out! Also, I can then do all the Fantasyland stuff on the way out a second time, if not crowded. To me, it feels like not walking through the castle and going towards Fantasyland first would be unnatural...