I've learned the hard way - or should I say the fun way - that computer cases are just a bad idea in general unless your machine is around splashy liquids or something. Firstly whoever thought up the idea of putting our beautiful hardware inside a tin box is just a loon. That given, I find that just by attaching a back-plate to the motherboard and setting it directly on my desktop:
1) saves the most space,
2) decreases overall system noise,
3) decreases system ambient heat dramatically!!!,
4) affords an unprecedented amount of component and connector access,
5) looks completely impressive and awesome,
6) saves at least $100 on every build,
7) related to #3, increases the efficiency of all coolers,
8) saves >2 hours of build-time, (you literally just set the stuff in place and turn it on)
9) potentially saves many hours when/if troubleshooting is needed
So that's it for me. I'm never using another case again... ever.