Building completely from scratch, I'd probably do something like this:
PCPartPicker part list/
Price breakdown by merchant/
Benchmarks
CPU:Intel Core i5-4670K 3.4GHz Quad-Core Processor($225.99 @ NCIX US)
Motherboard:ASRock Z87 Extreme4 ATX LGA1150 Motherboard($134.99 @ Newegg)
Memory:Crucial Ballistix Sport 8GB (1 x 8GB) DDR3-1600 Memory($66.99 @ Microcenter)
Storage:Samsung 840 EVO 250GB 2.5" Solid State Disk($169.99 @ B&H)
Storage:Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive($59.98 @ OutletPC)
Video Card:PNY GeForce GTX 770 2GB Video Card($314.99 @ Amazon)
Case:Corsair 200R ATX Mid Tower Case($59.99 @ Microcenter)
Power Supply:SeaSonic G 550W 80+ Gold Certified Semi-Modular ATX Power Supply($85.99 @ Amazon)
Operating System:Microsoft Windows 8 (OEM) (64-bit)($97.98 @ OutletPC)
Total:$1216.89
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-01-17 15:22 EST-0500)
A couple notes:
I only went with 1 8GB DIMM on the RAM because I personally value having the extra free slots for later expansion over the very, very minor performance gain of using 2 4GB modules. For gaming, you'd see less than a 1% performance difference with 2 4GB modules compared to 1 8GB module, and it wastes an extra expansion slot for adding more later.
I threw on the 1TB HD just in case you didn't have any HDs you could pull from a previous computer to use for storage. Since you have a good sized SSD on this build for the OS and multiple game installs, your extra drives don't really need to be anything special or overly fast, they're just there for bulk storage of media or old games.
You also don't necessarily need to pay $100 for Windows 8, theres links in this thread a few pages back on how to get legit Win 8 keys for like $10-$20. That could save you some money.
I didn't include any peripherals like keyboards or mice because those are always completely personal preference. Everyone likes different stuff there.
If you have a bigger budget, or need to stick to a smaller one, let me know and I can through out some more ideas.