How old are your GT's? I'm not particularly impressed with the X2 GP-12's but I have not done a side-by-side comparison unfortunately, the GT's I have are all 5+ years old and the X2 GP-12's I had were brand-new, so not a fair comparison.
All the rounds I can find online lack those two fans in...
Assuming you can wait for rebates on it, with rebate it's $20-25ish AR typically. I think you just missed one last week at Newegg.
Seasonic SS-300ET and SS-350ET, also Antec Earthwatts Green 380w are worth a look.
You're going to pay a slight noise penalty with 7200rpm disks like Hitachi Ultrastar 7K4000's, WD RE4's, or Seagate Constellation ES.3's... but really depends how picky you are about noise.
If low noise and a smooth running drive is the utmost priority, quite a few I know like WD Red's, but...
http://www.tftcentral.co.uk/news_archive/20.htm#hp_zr24w_update
Actually looks like tftcentral figured out that the factory contrast settings are not optimal on the ZR24w... they did a LOT more experimenting and found that it is actually capable of pretty good results...
Doesn't look nearly as nice as the stuff we do here... but then I remember this is a HOME setup. Jeebus. INSANE. :D
/me pats his "mere" 7TB of harddisks...
Per SPCR: http://www.silentpcreview.com/article255-page1.html
If it's 18" long it's going to be tight but workable. Looks like that was really only an issue on first-generation ATX12V 2.x PSU's-- later revisions of PSUs from companies such as Seasonic show 22" or 23" cables that work just...
How many drives-- at least the 4 you have now, or did you want more-- how many more?
If you're handy with sheet metal, pretty much any old, decent full tower can fit a bunch of drive at the front if you have fun with sheet metal, a drill press, and rivets. :) The Yeong Yang cube cases are...