Still visiting family, so my internet will be a little slow.
And yeah, that's a great price range. You've got a lot of room for extra stuff.
Basically though, I'd recommend an AMD FX-9590 processor, an ASUS M5A97 motherboard, and an AMD Radeon HD 7970. Sold out, whoops. Go for the 7870 instead.
Get at least 8GB memory and 500GB HDD.
Make sure your power supply is at least 550W with the parts I listed above.
For the rest, it's basically the case, and the monitor.
Go for a keyboard, mouse, extra case fan, and DVD drive.
Use Linux or else.