I do like the idea of quiet computing so the define would be good, but I could also just fan control the other one and put noise padding on the panels.
I am typing this on a phone so please disregard any mistakes.
What do you need "now" from the case and what do you want "later" ? Might help clarify
I tend to be be a minimalist when it comes to cases - not that they should be small, but that they should fit my components, have plenty of air flow, and allow me to upgrade.
That is a rather good question as in I need neither right now.
I would prefer quietness over anything but the hot-swap bays will come in handy when that one friends computer dies and you are tasked with the backing up of their data because they forgot to do it themselves. Also since Hard Drives are dropping in price I will be able to easily expand my storage without too much hassle.
Well if you're at all serious about that NAS you could go HAF stacker then, the 915r can fit 6 hard drives and would slip right on top of your main rig.
If I was to go with a NAS I would go with a SilverStone DS380. 8 hot-swap bays. I would also go with one of those awesome Atom powered server boards they reviewed a while ago.
If you wanted more of a dedicated NAS case that would be the way to go, I really hope coolermaster puts out a dedicated NAS unit for the stacker series sometime.