I bought Red Dead Redemption on a whim.
I'd enjoyed Red Dead Revolver on the PS2, and I was aware of the existence of Red Dead Redemption, but I wasn't hyped about it or really intended to get it, but then I read some positive reviews and more importantly, positive feedback & opinions about it on forums when it was released in America.
I then realised that I still had 2 days to preorder it for a discounted price & preorder bonus, so I logged into my favourite online retailer, clicked the mouse a few time and had it preordered & delivered to my house 2 days later.
It was the best impulse buy I've made in a long time, and a positive advantage to games getting released a few days earlier in the US than the UK.
EDIT: I think you need a poll option for people who preorder or order their games online, because I wouldn't have bought this one if I have had to make the long journey to my nearest game shop.