First, let's get the obvious considerations out of the way, and then we'll talk about tofu. The space you can give to a case is going to play a role in what you get. Oh, and if you have one of those desks that has a pull-out computer tray or cabinet, don't stick your computer in there. Yes, a case can be too big. I've seen more then one monster-sized case that simply had horrendous cooling.
Large towers are often guilty here.
Without side louvers, those drives you place up in the top of the tower may be without proper cooling. With today's drives getting hotter and hotter, you need to be concerned about Hard Drive heat. And don't think your Power Supply fan is going to help. Think of your case as an Apartment or house without Central Air Conditioning. When it's hot, you can crank up that 8,000 BTU window unit all you want, but the room farthest from that unit is not really going to benefit.