Besides October and late September my favorite time to visit Disney is the last week of February into early March. The weather is great and the crowds are low.
In fact, I was there this year during this time and quite honestly, the only ride that I needed to FastPass was Soarin'. Most rides you could walk right on.
Already have my stay booked at the BLT for the last week in February in 2010 and can't wait to arrive!