This was my first PC build, it will be used mainly for gaming, streaming, and general entertainment, making this a bit overkill I guess.
CPU: I was originally going to go with an i5-4690k but I had an i7 in my old computer and was happy with it, and also being a heavy multi-tasker, I ending up going with the i7-4790k. Overclocked to 4.4GHz, and after a few days of use so far, I am quite happy with it.
CPU Cooler: I was already pushing my budget a little, so water cooling wasn't much of an option. After reading some reviews this seemed to be the best air cooler for the money.
Motherboard: Didn't put as much thought into this, it was simply the cheapest part which had all the features I was looking for. Overclocking the CPU was easy with this but that is pretty much a standard now. Can't say I recommend this mobo mainly for one reason, it claims to have great sound isolation and such but at least on mine there is a lot of noise coming through the back audio ports.
Memory: Much like the mobo not much thought on this. It was one of the cheapest 16gb kits that also matched the coloring of the motherboard.
SSD: Recycled from my laptop, figured I was better off reusing this and putting more money into other parts than to buy a new one.
HDDs: I am a bit paranoid about data loss, so both drives are in Raid 1. I went with WD Black because of failure rate to price ratio, as well as the 5 year warranty.
GPU: Knew I wanted a 970, although not as popular as some of the other choices this one seemed to be good for the price. Having only owned laptops in the past, dang, so this is what real gaming feels like.
Case: Love the minimalist design, was going to go with the R4 originally but the R5 came out between the time of choosing the parts and actually having the funds to build them so it was an easy decision to upgrade to the R5 instead.
PSU: Being modular or semi-modular was a must, and at the time the 500w and 600w models were the same price.
Monitor: Probably were the most money was wasted but I have no regrets. Knew I wanted something that was 144Hz and two internet personalities I am a fan of both have this monitor and both highly recommended it.
Keyboard: Completely temporary, simply didn't have money left in the budget for something better so I choose something I thought I could get by with for a while. As you can tell I am using a different mouse in the picture, it is also a cheap mouse I have had and enjoyed for a while, but not going to bother looking it up.
Feel free to give any feedback!