I just went on newegg selected an almost identical build to what you just listed and it comes to $930 without OS. $1000 isn't a bad price if you can find a buyer.
That's just it - finding a buyer. What I'd do is find similar rigs on Craigslist and see how much those are going for (after throwing out the outliers of course)..
I also predict the OP may be taking a little vacation from THG if he keeps up with the insults...