re: ATX cases
Cases are actually another part of a computer where it doesn't pay to scrimp. This is ESPECIALLY true for the half-assed power supplies that come with the cheap ones.
I use Antec cases. They are well built, have loads of room, and nice features like a door that just plain opens without having to undo screws, lots of fan space, and hard drive brackets that snap in and out.
I use power supplies from this outfit.