Alright alright, I'll suggest a build for you, priced from newegg. These are off the top of my head so confirm the pricing and availability for yourself
A $1500 build in Antec 300? That's a low-end case, and its only strong point is that it's robustly built. Please sell it away, and buy a proper case with proper cooling, proper cable management and proper PSU positioning.
Also I'm not sure why you think it's necessary to spend $1500 on a single monitor gaming build - perhaps you were thinking of dual-GPU, or some relatively expensive monitor? I would not recommend dual-GPU, a capable single GPU can handle any game fine on one 1080p monitor.
Mobo Asus P8Z68-V LE $130
CPU 2500K $220 (microcenter in-store $150) + CM 212 Evo $35
GPU Galaxy GTX 570 $280 after rebate
RAM G.Skill ripjaws 1333 2x4gb $45
HDD Samsung F3 1TB 7200rpm $60
SSD Crucial M4 64GB (OS+programs) $95
Sound Asus Xonar DG $30 from microcenter (for headphones)
ODD DVD-RW $20
PSU XFX 650W $60 AR
or Corsair HX650 Modular $110 AR
Case Corsair 400R $95
or Fractal Design R3 $100
or Silverstone Raven RV02-BW $150 AR
or Coolermaster HAF 932 or HAF X
Subtotal ~ $1000
If you absolutely want a dual-GPU setup (yes it will run everything a bit more smoothly and you don't need to care about settings etc), then I would recommend that you get the Silverstone or HAF case, a Gigabyte Z68X-UD3-B3 board for $160, an XFX or Corsair 850W power supply, then SLI the MSI 560 Ti 2GB $250 each. That would cost you maybe $350 more in total - it's not only the second GPU that costs more.
Monitor ... what are you looking for? Cheap 1080p LED? 120HZ? 27 inch 1080p?