If you are doing an upgrade to a PC then make friends with your local "geeky" computer shop, I have.  They rebuild my PC's for the cost of the parts and use any old bits from my old PC (HDs, CDs, case, etc).  It costs me around £150/year ($300)

The old parts come back to me and I play with them (there are 7 networked computers in this house ... no TV as we watch on-line)

Just my £0-02 worth

Iain