We just got back from a November 5-11 trip. Actually the crowds were pretty BAD because of several factors:
--Jersey Week (New Jersey kids have the week off school and it seems the entire state comes down to WDW!)
--Food and Wine Festival was wrapping up at the end of the week
--Soap Opera Weekend was the 12th and 13th
--There was an art festival thing happening in Downtown Disney the 12th and 13th also.
We planned a year in advance after hearing this was a good, uncrowded time to go.

About 3 months prior to leaving, I checked with The Unofficial Guide's crowd calendar again, and they'd increased the crowd rating from a 4-5 out of 10 to a 7 out of 10! (you can find this info at
www.touringplans.com)
HOWEVER, if you plan things right--i.e. Get to the parks before they open, follow the Unofficial Guide to Walt Disney World's instructions to the letter (BUY THIS BOOK!!!!!!) , and take an afternoon break everyday, your line-waiting will be significantly decreased.
We ended up having a wonderful trip despite the crowds!