In term of investment, the best long term investment to get is the CPU+MB.
With CPU, there being a meager 5-8% improvement over generations making an investment in CPU performance to be one that would see the lowest depreciation over time i.e. the
best performance investment.
MB as no major change to the mainstream market is expected for at least a few years,
XPoint or
PCIe4.0 is still off in a relatively distant future and there's no major revision to
USB/SATA to be expected soon (if the
Type-C connector adoption suddenly take off then there may be something). The
100 Series chipset on these Skylake MB are expected to be at least
BIOS updated to be compatible with the next LGA1151 socket CPU, the
Kaby Lake so that's at least another few years before it become potentially unable to support the latest and greatest (and then
Cannon Lake would still be LGA1151, just not that certain that MB manufacturers would still be updating the BIOS of their at that time
~5 years old products; and with overclocking, you can have your Skylake CPU keep up with the mainstream CPU pick of 5 years on) pairing that with the fact that you'd need to remove nearly all components to replace your MB and the fact that
a cheaper OEM Windows license is tied to the MB meaning changing it later on would
invalidate the license and incur further cost and very often it would
also mean re-installing the OS itself making it an important component worth paying to get right (what you want and need) from the beginning. i.e.
best upgradability investment.
A Z170 board investment also representing overclockable CPU as well as higher performance memory that can help gaming performance:
http://www.hardwareunboxed.com/forum/viewtopic.php?t=1570
http://www.eurogamer.net/articles/digitalfoundry-2015-intel-core-i3-6100-review
Next two on the best to invest list are the PSU and case: good PSU last longer than the build itself and unless newer components come out and require special fitting, cases never become outdated (beyond your own aesthetic preferences of course). They have little effect on performance (except for cases that have poor cooling support i.e. few chassis fans/ fan mounts, limiting CPU cooler height which would directly affect cooling capabilities and therefore indirectly affect performance) though, so on a budget, it's best to pick the just enough rather than best-in-class (and for single CPU/GPU, a good 550W PSU is more than enough).
Video cards however doesn't work as well as CPU/MB as a long term investment since this gen
Pascal/Polaris cards are the initial jump to the new manufacturing nodes of
16/14nm; the next gen is guaranteed to deliver improvement/optimization on the node together with the potential development on the software end of
DirectX 12 / Vulkan (or hardware end with
High Bandwidth Memory 2 to replace the aged
GDDR5 / 5X) plus
Virtual Reality / Augmented Reality and changes could potentially happens in the ~3 years period to make your investment go south pretty quick. A good GPU would still provide good fps for sometime, but it definitely gonna require lower settings if you're talking about ~3 years on, especially at this investment tier (and the next tier is currently ~$180 more).
And no, you do not need to invest too heavily in an CPU cooler, the
GAMMAX 400 is a Toms Hardware Editor Choice cooler with solid performance and can totally punch above its price weight class:
Cooling an overclocked 6-cores Hyper Threading i7-5930k to 4.2Ghz:
Cooling an BLCK overclocked Quad-cores Hyper Threading Xeon E3-1230 v5 to 4.5Ghz (the Q1 2016/OC 2016 on the chart):
And personally, I wouldn't go lower than the Pro4 with its VRM equiped with heatsink and 10 power phases if I were to pick a CPU overclocking build. MSI boards also appears to have issues with pushing the right power to its CPU (in the reviews of their Z170 boards [and it's also a prime suspect in a recent review of a MSI H110 here on Toms regarding its CPU performance/temperature numbers]).
But you know.... Prices fluctuate... Deals end...
The Define S is already back to its usual $79.99+9.99Shiping.
The Seasonic SSR550-RM sales will end ~1-2 hours from this post.