Yes, I have stopped pre ordering. Although I am quite satisfied with X-COM: Enemy Unknown.
I think SCII-HotS will be my last pre-order. Got burned a few times with pre-orders for games that didn't live up to expectations.
If you can get it for cheaper online, and shipping or delivery is basically free, like Takealot.com then do it. Especially if it is something the stores do not have and it is a limited edition.
I'd only pre order if i really like the games series and that it comes with limited/collectors editions, while coming at a good price. Otherwise I never pre order.
Someone can still ruin it!