For a start, here is a link to pc part picker with all of your parts already selected.
EDIT: link goes to orginal build, needs updating http://uk.pcpartpicker.com/p/pprn8d
(8th dimensional pprn? Sign me up
)
I noticed there are some things that might be missing. You never mention a keyboard and mouse, do you have a pair available? Another thing is connections to the internet. If you're able to use an ethernet cable to connect straight to your router/modem, do that. Otherwise, you're going to have to invest in an ethernet networking card.
Reading up on your case, how many fans does it come with? I can't figure out if it's one or two. If it's only one, you may have to get another, depending on how hot the rig runs. Midi cases are reasonably large (mine certainly is) so temperature shouldn't be a massive factor (again depends on how the rig does run in the end, basing this off of your power consumption.) I'd question how necessary the CPU cooler is. People may disagree with me, but I think stock coolers are fine if you're not OCing or doing super intensive computational work for hours on end. The stock cooler on my AMD FX6350 is a bit loud, but otherwise keeps things in good working order.
Part picker is putting your wattage at 375W and your power supply is rated for 430W. That's fine for now, but you've got to think about future upgrades. I'd probably get a bigger one now (~500W), to avoid having to buy a new one a few years down the line. Don't cheap out on the power supply. It keeps everything alive and if it fucks up, you risk damaging all your parts.
Optical drive? If you use cds and dvds often enough, I guess it's worth a buy. When I built my rig a few months back I thought about getting one, until I realised I hadn't touched a physical CD in years.
Why are you buying a sound card? Your MB has an inbuilt sound card, and unless your producing professional tracks, there's no need to buy an additional one.
OS is what ever you prefer. I got windows 8 for cheap on a student deal. If you ignore the BS tiles thing on the start menu, it's just as good or better than 7.
I'd wholeheartedly suggest getting an SSD. Shit is super fast. Even getting a small one for the OS and programs, and then keeping the rest of your files, music and videos on the HDD is working awesome for me. I've got a 120GB SSD and a 500GB HDD. I've currently got ~>50GB free on the SSD for my next game install. Once I finish with a game, I typically remove it from the SSD and/or move it to the HDD.
A great way I found for designing my rig was to settle on my budget first. I was going to spend X amount and no more. I then found some example builds and split the costs of each component into a percentage of the total cost. That gave me a rough idea of how much I could spend on each part with respect to my budget. You don't need to stick rigidly to this plan, it's just a generally idea.