I appreciate everyone's input.
I'd like to go ahead with a purchase sometime today, having added the antec 620 psu, all I'm having trouble with finding a good/great case. I know it's my choice, but I'd love some ideas on a good case that will hold at least 6 HDD and still have room to play around in there.
Ideally, I don't see myself with a 20TB server for a good while, nor is that really the ultimate plan, but of course, I've got to think ahead. Really, I'm going to stick with my CPU (powerful enough and willing to get a GPU when the time is right for a HTPC) and Motherboard (option to upgrade to a HTPC in the future), seems as though anywhere RAM (four slots, upgradable whenever) / HDD (just need one purchase right now) I get now will suffice and the addition of the Antec should be plenty - if not able to find something of the same quality and cheaper.
Again, I appreciate everyone's input and can't wait to hear more.
EDIT:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817822005
Would this be a silly option?