Out of those 3, the corsair is cheaper by a pretty large margin, I would definitely go with that since its a top knotch manufacturer.
The pcpc one is great also, but at that price, I wouldn't even consider it over the corsair.
I picked up my silencer 750 for just 90 bucks a few months ago after rebate, great deal.
If you shop around, you might find some more deals, and dont forget the bing cashback.
IMO, I really like the storm scout, just the right size, great design, plenty of space and places for more fans. I'm also a sucker for the painted inside as well.
Plus, it can be had for just 90 on amazon i believe.