I collected a big fat 0, because every time I went to a pumpkin patch it was camped by the same kind of people as in this thread. The one time I found an uncamped one, I wasted over 2 hours shuttling pumpkins to the Luna trashcan and nothing ever spawned.
Never again.
I moved pumpkins off a field on Siege one time this year and then asked myself why I was doing it. I'm not fond of costumes or masks, so what was I gonna do with any masks I managed to get? Throw them in a box and forget about them, that's what. So I left.
About two days before the event ended, I was wandering around on Mugen with my crafter and stumbled across a field that actually had one of the big pumpkins in it. So I clicked on it to see what would happen. Of course my tailor had no chance of killing the grayish blob that spawned, so I left.
I don't get excited about the begging or trick or treating either. Would never use the Halloween decor (I do occasionally save named pumpkins though for nostalgia's sake and if I think of it, maybe one or two go out on display) and can't see the point of collecting the candy because it would also just go in a box and never get used. I have plenty of characters on semi-deserted shards that probably would have had no problems finding the killer pumpkins, but I just wasn't interested enough to bother with them. If the result had been another kind of pumpkin or jack-o-lantern, maybe I would have bothered to get a few. Masks or costumes....meh.
I guess I'm just a Halloween grinch.
The best ones were all kept in secured in containers and locked down as decorations. 
and 
Posts picture again: 2010 Halloween. 
