For those in the UK that want Halloween fun, may I recommend some alternatives:
Alton Towers has mazes, attractions in the dark and bring the Haunted House Duel to Life. And the Bon fire weekend, although the Halloween stuff is gone, they are the most amazing fireworks ever (better than DLP, DL, WDW, the Olympics and even when I was in London for Millennium eve). All included in the ticket price.
Legoland Windsor for Halloween had great halloween decorations and the theme changes every year. This year was Scooby Doo, and they had a themed fun house; a mad scientist workshop where we saw dry ice experiments and made goo; there was a scooby meet and greet, halloween building workshops (£2.50 a model to take home afterwards), and best of all the Scooby Doo fireworks (previous years we had Indiana Jones with a dig, and snakes/bug handling workshops). Again these fireworks are better than Disney and offered 3 weekends a year, as a part of the ticket price.
Chessington World of Adventures - three family fun mazes, rides in the dark, halloween themed kids puppet show, and a specially themed animal show, as well as this year having trick or treating and the headless horseman. All included in the day ticket price.
Hampton Court Palace was brought to life with actors and you could make an astronomical clock.
For more adult offerings - Thorpe Park, Port Aventura, Europa Park and Blackpool have excellent horror nights/fright nights.
I am so glad this is how we used our time this year. I kid you not, I would now rather go to DLP in summer where there is more on and it is less crowded than Halloween half term, and enjoy the delights of the UK parks for now. While many were disappointed at DLP this year, our expectations were more than exceeded at each of the events we went to (for comparison, I have spent Halloween at DLP 5 times over the years, DL 10 times and WDW once). the only Disney parks I would consider for Halloween now are HKDL or TDL.