I agree. Arrive early and take your breaks inside of the park. When we went in 2005, it was definitely crowded during the day. When everyone started gathering in front of the castle, it became clear just how many people were there! Around 9:00 p.m. they started playing party music on Main Street and they had several stations where you could pick up hats and noisemakers. People started staking our their spots in front of the castle early. We staked ours out around 10:00 p.m. and were off to the right, but could still see the front of the castle pretty well. Mickey and Minnie were up on the castle balcony along with an announcer guy and a few other people and they led the countdown. At midnight, they had the biggest and longest fireworks show we'd ever seen at DL. Getting out was somewhat of a nightmare, but we just went with the flow.
I'm glad we spent a New Year's Eve at DL. However, it's one of those things I think I'll only do once. It was fun, but between the crowds and sitting on the cold ground for 2 hours, I don't feel the need to do it again!