Welcome to my little world! I love audio production, it is my first love as far as art is concerned!
What you have picked out will be just fine for audio work. Even an old Core 2 Duo will keep up with several (10+) tracks of uncompressed high quality editing and effects in real time, or minimal rendering time. The hardware for the computer is the easy part.
What GPU are you looking at? 750W is way overkill unless you are doing SLi/xFire. With using onboard graphics you could get away with a tiny 350W if you wanted to, but I would stick with a quality 500W minimum for future upgradeability.
The important part of a recording studio rig is as follows:
1) A Silent PC. Background noise is the enemy. HDD dampening, 5400/5900RPM drives, and SSDs are a god send as your storage device should be the loudest part of your audio build. Find the fastest card you can with a passive cooler, or low RPM cooler on it. I put a passive cooler on my old 9800GT for my audio editing rig.
2) Optical output to a high quality receiver. If you are doing stereo work then you can get away with a cheaper receiver (my Pioneer 515 is horrible for surround sound, but is quite good and flat if used in stereo). Be sure to match that with reference quality speakers, or high end headphones (yes, there is a difference between $200 and $500 headphones if you have the money to splurge. I did not, but then again I have some nice custom built speakers I mix with because I hate wearing headphones for long periods of time).
3) Quality inputs. You will want to invest in a good multi-track recording interface. Your base model to look at should be a tascam US2000, but there are many better ones out there if you have money. USB3 recording devices should be out soon (fingers crossed) which will allow for more realtime IO, or at least drive down the price of quality USB2 products.
4) Good software. Cubase, Audition, Fruitloops, Digital Performer, and Acid are all great, and better designed for different things. There is also Audacity which I use on my netbook when recording 'on site', but it is useless for editing or doing any multi-track work.
i seen my bros music PC, his got 3 monitors (1 screen just for EQ) if you want more then one monitor you would also need some kind of video card.
Also if you can buy SSD (~60-64gb) type install windows on it, run programs from it. and get regular 1tb for storage.
cpu mb memory psu looks good to me
Do not get a sound card. Get a good audio interface, most brands are of decent quality, but you get what you pay for. Sound cards are for kids who like to add extra bass that isn't there and then wonder why things 'sound like crap' on everyone else's systems, and enjoy wasting time with drivers that dont work most of the time. An audio interface will be a flat output, so you know exactly what is there, and what is not. Same rule applies to your reciever and speakers. Do not get a thumping system, get a flat, balanced system so you hear what is real. Optical output should be fine for your monitor (audio monitor of course), and all of your processing will be done better on a CPU than a sound card anyways.
Multiple screens are wonderful. I have one very large screen, but back when I was on CRTs I was running 3, and I miss that kind of resolution/space.
SSDs have no moving parts, so they are silent, which is wonderful. They are also crazy fast, but a touch expensive. Use an SSD for your system drive and programs, and then a good quality large 5900RPM HDD for your storage.
you install operating system and programs, thou its small but fast. You pick size its depends on your needs and $ u got.
If you don't need much space you don't even need regular hard drive inside case making noise, get eSATA or usb3 external