We've done October recently. This year (2006) was terrible! Weather was lovely, but crowd levels were really high some days. MK was always busy, AK not much better! Love bugs were everywhere - it was sickening actually how many there were.
We're not going to book Oct next trip, probably early Sept is a better time to go (and I loved Oct, in 2004 we virtually had all the parks to ourselves and have several pics of a virtually empty MK!!)