MB: For the price, better boards with more features can be purchased.
GPU: Newer 7xxx AMD chips are coming out, and so are the 6xx Nvidia chips both using 28nm. With that said use less power, perform better for the similar or less price. The 7950 itself is the price of the 580 and beats it out the 7970 is of similar price (kind of) to the 580 again beating it out in nearly every catagory.
HDD: The Caviar Blacks are expensive but not justified by the performance and space offered.
The 7970 is a better overclocker and in most reviews they stated the 7970 could handle taking on the 590 and the 6990 (Dual-card single PCB graphics) in certain situations. Though it is expected from a new arch and die shrink. So that's to be assured.