Went October 22-29 this year. Had a blast! Arrived two days before Hurricane Wilma ("she" only closed the parks for part of one day). The day before the hurricane, it was hot, humid, and made me really crabby (I overheat pretty easily). The hurricane went through the next day, and the rest of the week was beautiful!!!! Mid-70's and not humid at all. Not quite hot enough for a lot of pool/water park time, though. But if it hadn't been for the hurricane, I think we would have wanted lots of pool time. The night before the hurricane, though, we had an absolutely torrential downpour! Went on Maelstrom, and in the 15 minutes we were inside the building, it went from pleasant, non-windy weather to torrential rain. Luckily, I have a poncho in my fanny pack, so I saved the 6 or 7 bucks that I would have spent on a Mickey poncho. We were all very waterlogged by the time we got back to the room. So be prepared - if you go in October, there's a good chance you might have a hurricane! I would recommend you go, anyways. We only got "grazed" the edge of the hurricane, and weren't impacted significantly at all.
Definitely go the the MNSSHP -- one of the highlights of our trip! We couldn't get over how cool it was to literally walk onto any ride at MK, with no wait at all. Definitely worth the extra fee. We didn't have little kids, so skipped the trick-or-treating and other kid activities. Loved the parade, though; the Pooh characters dressed in Halloween costumes were so cute! Eeyore in his mummy costume was hilarious.
And we went to the Food and Wine festival every day! Three out of four of our party went to the wine seminars/tastings. I don't drink wine, so didn't go to the tastings, but really enjoyed the food booths! Great chance to sample some great food.
Have fun planning your trip!
I just booked a trip for Columbus Day weekend '06. I've never been that time of year, so it's nice to hear these comments 
