If you do minor gaming, you might need a cheap drive (wait for a deal than to buy one to start). probably in the $90-$200 range at most.
I have a NAS (built 1.5+ years ago or so)
I used synology ds213j (2bay, it was $170). solid as fukk, great for everything and automation (i think you should be able to automate newsgroups and torrents) and hasnt failed on me
I have 2x2TB seagate 7200rpm drives cracked open from externals ($100 each, this was right after the flood and HD prices were still decently high).so about $370.
you might want to consider bigger harddrives (obviously, its cheaper now, less necessary to upgrade as media size and bandwidth increase) and maybe more bays.
an underrated place is amazon warehouse. they usually sell open box returns (same return policy as amazon, almost everything i got was new).
http://www.amazon.com/b/ref=sv__img?ie=UTF8&me=A2L77EE7U53NWQ&node=1267877011