I have made the (for me) difficult decision to make this my general use home computer as well
I can see that. My studio PCs have always also been a general-purpose PCs ... and it hasn't been a problem to me ... just requires extra care when installing any software. But I always use wired ethernet instead of wireless, when possible (have some 100m/300ft of ethernet cables in my house). 2 reasons for this:
1. Every additional hardware/driver is a possible source of problems. So why not use motherboard's ethernet connection and a cable to connect to the router.
2. In the past I have had horrible DPC latency problems with numerous wireless devices. So I have decided: no single wireless device connected to my DAW, not even wireless keyboard or mouse, (unless it's DAW-specific device, like my Frotier Tranzport). Maybe this isn't a real problem in these days anymore, but I get paranoid whenever I hear the word "wireless".
I will ask them to look at dropping this for on-board graphics only. It might not be any savings to me to do so
It should save you $60
I will inquire about a fanless PSU ... thank you.
Should cost you extra $60 (compared to Corsair 500W)
I am not sure what you mean here: That I should look into the case PLUS some acoustic treatment? Or ...
This is standard option for ADK computers ... I don't know who is your dealer, but your proposed system is obviously a standard ADK setup:
(under "Quieting/ Xtra cooling" there).
It costs extra $100 (compared to your proposed "ADK Quiet Case fans" option)... so it's a bit expensive option, but in my opinion you can't spend too much for making your PC silent. I just built one couple of weeks ago and I'm really happy with the noise level (after spending quite a bit for that), but can't stop thinking: "I should have chosen that fanless PSU and more quiet case fans" (yes, I have acoustically treated case).
What is it that an i7 is better at ... higher track count, or is it more VSTi's?
Both and maybe also possible to use lower latency setting. As seen from ADK page (see link above) you can have i7 model 4771 for extra $112. To compare performance difference between 4570 & 4771 see:
In my opinion the difference is significant and well worth the extra money.