Intel Core i5-6600K - $269
The Core i5-6600K from Intel offers sufficient processing power for smooth gaming at 1440p-120 Hz. Despite lacking HyperThreading, it offers excellent multi-core performance and shouldn't bottleneck anything in our build. Based on Intel's latest "Skylake" architecture, the quad-core chip offers 4 GHz-scraping clock speeds, 6 MB L3 cache, and the most updated instruction set. Popularity and/or shortages spike its price up by $10 these days.
For the $269 we spent on the processor and the $49 we're about to spend on the cooler, we could have gone ahead and bought the Core i7-6700 (non-K) for $329, which includes a stock cooler, but bear in mind that the i7-6700 lacks an unlocked base-clock multiplier, and the stock cooler is noisy. If you can live with those limitations, we encourage you to buy the i7-6700 instead of an i5-6600K with a decent aftermarket cooling solution. The HyperThreading and 8 MB cache could make up for its shortcomings, but you're stuck with its stock CPU clocks forever.
be quiet! Shadow Rock Slim - $49
The i5-6600K doesn't come with a stock cooling solution, so be sure to set aside some dough for a good cooler. With high-end air-cooler manufacturers raising their prices to match entry-level AIO liquid cooling solutions, it's hard to find meaty tower-type air coolers for under $50 these days. be quiet!'s Shadow Rock Slim changes the market, offering a 'no-frills' tower-type cooler that's game for thermal loads of up to 160W. This cooler features a slightly off-centered fin-stack and a slim, low-noise 135 mm fan, which creates loads of clearance for tall memory modules, making it our pick.
ASRock Z170 Extreme4 - $145
The GIGABYTE Z170XP-SLI, which featured on several of our older builds, finally has its sub-$150 supremacy challenged by the ASRock Z170 Extreme4. Right off the bat, this board looks premium, comes with a near-perfect feature-set, and offers a much stronger CPU VRM than the one offered by GIGABYTE's board. The Z170 Extreme4 won't make you miss features found on the Z170XP-SLI, such as USB 3.1 type-C or Dual-BIOS. You also get a neat, all-PCIe expansion area, and ASRock finally figured out how to balance a power budget without an ugly 4-pin Molex input. Pick this one with both hands.
Mushkin Blackline Ridgeback DDR4-2400 16GB Kit - $94
The Blackline Ridgeback from Mushkin offers excellent value for your money, with DDR4-2400 speeds at relatively tight 15-15-15-35 timings and 1.2V for just $94. DRAM prices across the board are on the slide; however, this is one of the best sub-$100 16-gigabyte dual-channel offerings out there.