As the price comparisons are a bit awkward, making specific recommendations are much harder.
For motherboards, ASRock Z87 Extreme 4, Asus Z87 PLUS, Gigabyte Z87X-UD3H (traciatim mentioned the UD5H) are usually reasonably well priced (relative to the Sabertooth) and good at overclocking.
Not much point in your secondary HDD. Caviar Black drives make sense if you need larger capacities and want the extra warranty life. At 1TB or less, they are so much more expensive than the equivalent Caviar Blue or Barracuda drives, and no faster. 1TB is often a sensible value for money cutoff.
The cooler is great, but as has been pointed out, expensive. If you want to go nuts with overclocking, it is money well spent.
The Define R4 is a good case, but again you can save money here if you really want to boost the value for money factor.