I think my vote would be to have the inventory get decremented AFTER the sale was made, thus it would be after the final submission. This way only actual sales have affected your inventory count. I would also prefer to capture the sales lead even if I didn't have the stock available as I might be able to offer a substitute or still close the sale (after ordering more of the item). I'm not sure how we could capture the sales lead, maybe institute some form of back order processing? Or provide some way to let the customer know when the product would be back in stock (automatic email)?

I also would vote for having at least 24 hour cart durations (maybe even as long as 2-3 days). I often times start to place an order online and get distracted with something else and then need to come back to the site to finish my order. If I come back and my cart is empty, I'm much less likely to fill it all back up!

Maybe we could make these options user configurable?

Jeff