All good cases I've seen recommended over and over on this site. They should all fit the 5870.
I don't know about the scout. I currently have the scout and looked through alot of fourms, and the size of the card would hit the hardrive case. I had enough trouble tring to get the two 75W 6-pin PCI Express power connectors in.
I've heard good things about the cm 690...how does it stack up against the others and would it come out ontop?
Oh trust me, it is a badass case, but the others I mentioned would be a better choice IMO. I bought it because it was $30 off and free shipping . Couldn't resist the deal, but if any other of the cases were on sale I probably would have went with them.