They're "desktop" computers? Lol.

But the G5/Mac Pro case is too big for my desk, so mine is on the floor next to me.

Native9 is pretty much the biggest reason to pick a G4, that and older G4's are a lot more reliable since they came before the era of cheap, counterfeit capacitors. I like both case designs, and there no doubt in my mind that the interior of the G5's is nerd heaven from an asthetic standpoint, but the G4's exterior is also quite unique and pleasant.