We went from October 8-13, 2012. It was very warm (unseasonably so -- we had daily highs in the high 80s, instead of high 70s-low 80s, which is more the norm) and we saw nary a drop of rain. Crowds were fairly low and with sound planning and use of FPs, we didn't wait in line for anything for more than 10 minutes. (There was one anomalous long wait at Big Thunder, but I'm not "counting" it because it was caused by a mechanical failure and not ride capacity/crowd issues.)
I'd recommend October (especially early October -- crowds go up as Halloween approaches) to anyone. For planning purposes, you'll either want to incorporate or else plan around the Epcot Food & Wine Festival and MK's Mickey's Not So Scary Halloween Party.