Built a computer for work this morning: Intel Core i5 650 processor, Gigabyte GA-H55M-S2V motherboard, 4GB OCZ Gold D3-1333 RAM kit, WD 500GB "Black" hard drive and LG 22x DVD burner, all in a plain TX-388 case (shown on right), with an Antec 380W Earthwatts power supply. Win7 installed quickly, will dual boot with Ubuntu (or maybe Red Hat).
Hardware cost: $450.93 (excluding sales tax)
A word about the cost. I purchased everything at my local Microcenter, but first went to NewEgg to check prices. I saved about $50 by doing that. Kudos however to Microcenter for the low price on the i5 650 - $40 less than NewEgg. A license for Windows 7 will run me about $100, so be sure to factor that cost in when deciding to make or buy, as well as a few hours of your time to assemble the parts and install the operating system. Also, I did spend time deciding exactly which parts to buy, insuring they were compatible with each other, price checking for the best deal and finally, going to the store to buy everything.
That said, a similarly equipped machine from Dell or Lenovo would run $800 or $900. Sure, you get a warranty, but, as I told the associate at Microcenter, that's my job!
PS. Why doesn't someone sell an internal 2.25-Inch 8-Ohm 0.25W Speaker?