Well I had always dabbled with RAM, GPU and case fan upgrades as a kid but had never completed a full build. After my S-series VAIO laptop with a 2nd gen i-7 had its motherboard fry ~6 months ago (RIP) I was left using a 9 year old HP core 2 duo laptop with a broken clicker (>.<). Fast forward after a few months of research and price checking and I am very happy with my build (so far!).
Motherboard: Opted for the z170 board for the potential CPU and/or GPU upgrade(s) in the future (and got a good deal on a budget z170 board from newegg; its not very pretty but I wasn't going to have a case window anyways).
CPU: For my current needs, this i3 is really impressive. Was expecting to potentially be disappointed, but so far it runs nearly silent and is very snappy.
CPU Cooler: Stayed with the stock Intel cooler since I most likely won't be overclocking this CPU (if I do it will be to only 4.0ghz or less).
Case: The case is roomy for my needs. I didn't like the SSD/HDD mount very much but it's w/e. Cable management was not bad (I made a few first time builder errors here but overall it came out pretty nice). My only real issue with the case is the standoff points were not perfect on the right-hand side for my motherboard (they were off by like 3/4 inch; the middle and left standoff positions were fine). Made plugging in the 20-pin power connector nerve-wracking as I tried to not flex the board. It worked out fine though.
RAM: Pretty freakin' fast and got it for cheap (also looks good). Should've gone 2666 (first time builder error lol) but 2400 is probably fast enough for my needs.
CD/DVD Drive: Decided to get an optical drive to back-up some old music and to make life easier when installing Windows from disc (my flash drive was a tad too small). Was $20 shipped and works great so far!
PSU: Heard great things about Seasonic and knew through research not to cheap-out on the PSU. Should handle upgrading in the future as it supplies way more power than the rig currently needs. Should have gone modular but was trying to cut $ everywhere I felt comfortable (saved ~$15).
HDD: 1TB. ~$50. Easy call.
WiFi: Belkin adapter works great so far. Was the cheapest way to get WiFi. (Update: this WiFi adapter works, but its pretty weak. It will get you connected but don't expect any insane bandwidth. Currently running a hard wire, will upgrade to WiFi card in future if needed.)
GPU: Bought on Jet.com. Saved a little over $20 with a code. Didn't have the funds for the R9 380 or GTX 960. I like the value of the GTX 950, especially at $120. CS:GO/DoTA 2 MAX. Haven't tested AAA's (cause I don't plan on playing many AAA titles honestly) but I will be testing a few soon.
OS: I left this off the price list because most people will probably have access to an upgradeable/free copy. I opted to buy a new copy of Windows 10 because my only running PC was on Vista (>.<). At least $85 was reasonable.
I also saved another ~10% off my newegg purchases (~ $17 savings) with a code.
OVERALL UPDATE - 10/21/2017 Still quite happy with it. I haven't touched a thing since the build except for the occasional internal cleaning with compressed air. Quite shocked by how much of an effect dust can have on performance of the machine. Keep those fans + cases clean boys.