You might like to have a look here first. click here
I have been a builder for some years, it was considered a cheaper way of getting a decent PC without the bundled garbage software,plus you had the components you wanted, it probably is not any cheaper than a shop bought one now.I still get a kick out of doing it. Putting your components together and pressing the power on button for the first time can be very frustrating at times when things don't quite go as planned. But hey go for it.
Having quick look at your components, a sound card is probably an unnecessary item as most motherboard the on-board sound is fine.
I conceder the power supply unit to be one of the most important components which you have not listed.
Here is a list with some reccomended PSU's click here
There are course many others,this is just a start.
Some of your compononents can be had a bit cheaper.
CPU click here
Mobo click here
GPU click here
Hard drive click here 500GB
COOLER click here
Have a look here for compatible Ram for your Mobo. click here
This as I said is just a quick look. No doubt others will come in amd help.
For a case, you should be looking for at least tooless, saves a lot of bother fitting optical drive,PCI cards etc.
Good ventilation is also a must, so a couple of 120mm fans.
Have a look at Coolermaster, Antec, Xigmatek,fractual again there are many otheres.