I would get at least a 128GB SSD for Windows, and to install a couple of programs on. It will almost fast as light. Some choices:
1.http://www.amazon.com/Kingston-HyperX-2-5-Inch-SH103S3-120G/dp/B007R67FNA/ref=sr_1_12?ie=UTF8&qid=1397320651&sr=8-12&keywords=128GB+ssd
2. http://www.amazon.com/Samsung-Electronics-MZ-7PD128BW-Series-2-5-Inch/dp/B009NB8WR0/ref=sr_1_7?ie=UTF8&qid=1397320651&sr=8-7&keywords=128GB+ssd
3. http://www.amazon.com/ADATA-Premier-2-5-Inch-Internal-ASP900S3-128GM-C/dp/B007RHT48S/ref=sr_1_10?ie=UTF8&qid=1397320651&sr=8-10&keywords=128GB+ssd
And keep the 16GB of RAM. It will keep you happy when you have to do a lot of multitasking and productivity. And don't get the Xeons, either. Since you said you would be gaming, Xeons, for some reasons, aren't good with games. 2 TB HDD:
1.http://www.amazon.com/Seagate-Barracuda-3-5-Inch-Internal-ST2000DM001/dp/B005T3GRN2/ref=sr_1_1?ie=UTF8&qid=1397320851&sr=8-1&keywords=2TB+HDD
2.http://www.amazon.com/WD-Green-Desktop-Hard-Drive/dp/B008YAHW6I/ref=sr_1_2?ie=UTF8&qid=1397320862&sr=8-2&keywords=2TB+HDD
The Seagate has a huge sale going on right now, but only have a couple in stock.
And did you intend to geta Mini ITX board? Here's a standard to fit inside the mid-tower case, which is my case:
1.http://www.newegg.com/Product/Product.aspx?Item=N82E16813130693
And since this is your first build, here are some videos:
1.https://www.youtube.com/watch?v=W4Js2A1qdB8 From Tek Syndicate
2.https://www.youtube.com/watch?v=qMRvz_IYSgM From LinusTechTips
And now, for the heatsink. A good heatsink is supposed to have some weight to it, but not weigh a ton.
For extreme cooling:
1.http://www.newegg.com/Product/Product.aspx?Item=N82E16835608018
For standard cooling:
1.http://www.newegg.com/Product/Product.aspx?Item=N82E16835288003
And please stay away from Cooler Master fans. They are VERY loiud; I can hear mine right now like it;s right next to me.
And if you want to get into water cooling:
1.http://www.newegg.com/Product/Product.aspx?Item=N82E16835181010 Corsair kit
2.http://www.newegg.com/Product/Product.aspx?Item=N82E16835106220 Thermaltake kit
Both are good kits, but I would recommend Corsair. Much of my products are Corsair, and have had NO problems whatsoever. I did have to RMA a headset, and they had the best customer support I have ever dealt with.
And so ends my longest and most in depth reply.