Your Current Specs: Running on a laptop atm, but I'm looking to upgrade to a custom built desktop for the first time. Current relevant specs are 8GB RAM, i5-2410 2.30GHz, and Radeon 6490M, but being a laptop it's not terribly useful here.
Budget: I'm looking for something in the $1000-$1200 range. 
Main Use: Gaming - 5, Emulation - 4, General Usage/Video playback - 3, everything else is moot. Also, as much future proofing as is reasonably possible.
Monitor Resolution: 1080p. I'll be mainly using the HD TV I've already got, as this thing will double as an HTPC
List SPECIFIC games or applications that you MUST be able to run well: at the very least 30FPS on max settings for anything on the market currently, short of maybe Crysis 3. As I said, I want something that'll be future proof, that'll be able to at least minimally run the latest games 4-5 years from now. 3D is not a priority however. I'd also like something that'll be able to pull it's weight in emulation, 60FPS in dolphin/PCSX2, so CPU clocks are also a must. Finally, being also an HTPC, being as wireless as possible is a huge plus, so that includes long range mouse/keyboard/wifi, as well as having a good sound card/surround sound option later on.
Looking to reuse any parts?: as I've said above, I've got a TV already that I'll be using this thing on, but other than that I'm starting from scratch, essentially. Wondering if I can just reuse the windows 7 install disk that came with the laptop though?
When will you build?: This is me planning way ahead for my Christmas/birthday present to myself, but I'm willing to wait maybe another few months past december if there are any major chip/card releases that may be worth my while. 
Will you be overclocking?: if it doesn't cost significantly more, sure.
All that being said, here's what I've come up with so far.
PCPartPicker part list / 
Price breakdown by merchant / 
Benchmarks
CPU:  Intel Core i5-3570K 3.4GHz Quad-Core Processor  ($189.99 @ Microcenter) 
CPU Cooler:  Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler  ($29.98 @ Outlet PC) 
Thermal Compound:  Arctic Cooling MX-2 4g Thermal Paste  ($4.98 @ Outlet PC) 
Motherboard:  Asus P8Z77-V LK ATX  LGA1155 Motherboard  ($124.97 @ Outlet PC) 
Memory:  G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory  ($65.70 @ Newegg) 
Storage:  Western Digital Scorpio Black 750GB 2.5" 7200RPM Internal Hard Drive  ($72.68 @ SuperBiiz) 
Video Card:  EVGA GeForce GTX 770 2GB Video Card  ($419.99 @ Amazon) 
Sound Card:  Asus Xonar DSX 24-bit 192 KHz Sound Card  ($39.99 @ Newegg) 
Wireless Network Adapter:  Rosewill RNX-N150HG 802.11b/g/n USB 2.0 Wi-Fi Adapter  ($13.99 @ Amazon) 
Case:  Cooler Master CM 690 II (Black) ATX Mid Tower Case  ($89.99 @ NCIX US) 
Case Fan:  Antec 75024 79.0 CFM 120mm  Fan  ($8.99 @ Mac Mall) 
Power Supply:  Antec Basiq Plus 550W 80 PLUS Certified ATX12V Power Supply  ($69.99 @ Amazon) 
Operating System:  Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit)  ($89.98 @ Outlet PC) 
Keyboard:  Logitech K750 Wireless Slim Keyboard  ($49.99 @ Dell Small Business) 
Mouse:  Logitech G700 Wireless Laser Mouse  ($55.10 @ Amazon) 
Total: $1326.31
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-06-24 18:06 EDT-0400)
I'm a little over budget, but I'm hoping by staying on the lookout over the next few months I can knock off a few hundred from there. Plus, I'll likely be selling my current laptop and getting something a bit more modestly specced notebook to eventually bring to med school for in class note taking and the like, hopefully ending up with some spare change in the process.