Budget: < $3,000 (including monitors and all peripherals; < $2,000 for computer itself)
Primary use: Gaming, also to be used for work (Excel, Word, & Chrome for work - no heavy video editing or graphic design, but often require multiple documents open and viewable simultaneously)
Goals: To be able to run modern, demanding games on highest settings at 1920x1080 with 8x MSAA or on high settings at 2560x1440 with no AA. To allow easy future upgradability at a lower price - as a result, I spent more on the case, case fans, PSU, hard drives, and optical drive, which I intend to keep through two or three video card upgrades and at least one CPU/MOBO (and possibly RAM) upgrade. To take advantage of best deals available at time of construction but to acquire all necessary parts within 4 weeks - many of these parts were chosen at least partially because they were on sale and/or presented a good value at the time (e.g. while I had planned to purchase a 256gb SSD, the Samsung 840 500gb was on sale).
This is my first ever build, and has gone very smoothly for the most part. Just recently completed overclocking the CPU and GPU - achieved significantly higher overclocks (4.9GHz & 1300/1650MHz, respectively) than what I ultimately chose to go with, as I have no practical need to max out the components currently and preferred to keep the voltages lower. The load CPU/GPU temperatures reflect the max temperature (for the CPU, of the hottest core) after running Prime95 blend test for 8 hours (CPU) and FurMark burn-in test for 30 minutes (GPU). The CPU vCore fixed is set to 1.150v (.05 more than stock) and the GPU VDDC is 1.250v (stock).
Picking out the parts, going through construction, and fine tuning the machine has been a blast and I'm disappointed that it's mostly over. I realize I still have room for some customization, particularly with cable management, and given my itch to tinker, I'm sure some mods will be made gradually down the road.
[6/18/2014 edit: So the budget got blown through the roof as I continued to make modifications (and add monitors...). I have tinkered with the overclocking on the new graphics cards and will update when I can take a look at the numbers again. Still loving this machine despite the tremendous hole it's left in my wallet.]