All of that looks correct to me.
I would recommend getting hold of Windows 8, before you all bitch at me for what a horrible OS it is, Windows 8 had massive improvements performance wise and its a good FPS boost for gamers.
The memory is good price wise for the speed, as much as company like tagging "gamer" RAM is usually the same price throughout and just depends how fast you want it to go.
Windows 8 doesnt really make a performance difference to games or apps at all. Some are faster and some are slower so its neither here nor there, most improvements are from stripping the Os down to be suited for tablets and battery life, pointless on a desktop plugged into the mains.
Im about to go back to Win 7 after using 8.1 since launch as its still got stupid bugs even from back in Win 8, Win 8 feels much less polished and thats even after its 1st service pack.
Theres also the issues that a load of important menus are now Metro only even when hacking a start menu back and it gets frustrating trying to configure a pc using a phone based touchscreen interface with a keyboard/mouse.
Although you could buy Win 8 Pro for cheap and use the downgrade license to get Win 7 Pro for free.
Id also suggest maybe getting the Sapphire Toxic R9 280x. If you are spending that much on a pc you'd be better not buying the lowest priced 280x. The Toxic supports huge overclocks and should run a bit quieter due to better heatsink and fans.
Ive been using a Sapphire Dual x 280x OC and it struggles to max some games @ 1080p still, better getting one that overclocks better and quieter as mine can cause a lot of noise.
Just remember that the Toxic is a bit longer than the standard 280x.
You could also save some cash buying memory that doesnt have gun shapes glued to the sides of it. Those memory heatsinks are pointless and non ricer ram will do the exact same job.