I kinda am hoping for Nov. 6th as a release date myself...
1) The extra week can help make sure any bugs and things are worked out, smooth, and cool.
2) I'll already be hyped up by Hallowe'en! I wanna spread out my excitement. Especially since October is such a cool month already, I wouldn't mind spicing up November a bit. :-) It's always so boring and blah.
3) Because of Hallowe'en it may overshadow the coolness that is Monkey Island! The only way to avoid that would be to release it say Oct. 26th - 29th, but that may be too soon for it to have maximum quality. That way MI would complement Hallowe'en instead of being eaten by monster Jack-o-lanterns.