With the top end of your budget, I'd get the Bravo Company upper of your dreams. You'd probably have enough left over for a PSA complete lower to mate it to. Buy ammo and mags when you scrape together another couple of hundred bucks.
The getting is good right now. Lowest prices ever. Go with a BCM upper and then see what shakes out.
Obviously, you're not me and what you like and want are different. However, as an example, here's something I might do:
http://palmettostatearmory.com/index.php/catalog/product/view/id/2416/category/4282/
http://palmettostatearmory.com/index.php/magpul-pmag-m3-mag557-blk.html
This comes with a FREE BCG!
http://www.bravocompanyusa.com/BCM-16-Mid-Length-LIGHT-WEIGHT-KeyMod-Upper-p/bcm-urg-mid-16lw-mi-sskg212.htm
http://www.bravocompanyusa.com/BCM-Folding-Battle-Sight-Front-p/bcm%20front%20sight%20rail%20mount%20m4.htm
http://www.bravocompanyusa.com/BCM-Folding-Battle-Sight-REAR-p/bcm%20rear%20sight%20troy.htm
Add a BCM charging handle of your choice and you'd have the most bad-ass, green-with-fucking-envy AR-15 in the neighborhood.