Haven't built a PC in about 10 years since college, most recently had a gaming laptop, which was fine for about a year, then developed some serious thermal issues, causing reboots whenever running anything more intensive than a flash game.
Needless to say, I wanted an upgrade, but didn't want to spend a ton.
I got the power supply as a gift when it was on a public Amazon wishlist by mistake, so that "forced" me to go ahead and take the plunge and buy the rest of the components.
Processor and RAM: I decided to go with an i5, since the i7 series has yet to have any real impact on gaming performance, and I don't need to do any video encoding or anything on a regular basis. I am starting with 8gb of ram, but I may upgrade that by adding 2 more sticks down the road, I just have to make sure to get some low-profile sticks, or else they will not clear the 212 EVO. The RAM is blue, and it was inexpensive, and it looks like G.Skill backs their products, so I'm happy with it. I ran through a run of MemTest86+ and had no errors (Except for a MemTest crash, more on that later).
Case & Fans: I love the case. I was originally looking for a Cooler Master 690 II, and then the Corsair 400r, before finding the Arc Midi. However, at the time, Amazon.com had it for $109, and I knew I would find it on sale if I waited a bit. I ended up seeing a deal on the Define R4, and snatched it up, even though I was worried about cooling performance. I live in FL, so the ambient temperature is frequently pushing 80ºF in my office. Seems like I didn't really have to worry, though, since the thing runs nice and cool (30C at IDLE, ~60-65C under load from Prime95). I currently have it set up with the two front intake fans, and the Higher-CFM Rosewill Hyperborea (Which is a rebranded Akasa Apache), is exhausting air out the back. All of the fans are plugged into the motherboard, bypassing the fan controller in the case, allowing me to control them in software. The other vents in the case are plugged up with the noise-reducing foam, and temperatures still stay reasonable.
Motherboard: I saw a number of very positive reviews for the motherboard, and the Feature/Price ratio was about right. I saw an awesome Microcenter combo deal where the Motherboard+Processor were offered together at a discount of about $100, but unfortunately, it was in-store only, and I wasn't going to drive the 8 hours up to Georgia. I still ended up getting a pretty good price on the motherboard standalone, and so far I have no complaints with it. It was relatively easy to set up, and the UEFI bios is easier to navigate around than any other BIOS i've ever used. It also auto-detected the XMP profile on the RAM automatically, and I didn't have to tweak a thing. I have not yet played around with overclocking, but it looks pretty straightforward.
Power Supply: Pretty easy choice. I don't plan on an SLI setup or anything, so 620W is more than enough, and this one is clean, reliable power with a semi-modular design. Also nice and quiet.
Hard Drive: I was initially looking at the 840 EVO in 128GB capacity, but upon reading that the 250GB improved the speed significantly, thanks to the two parallel flash parts, I bit the bullet and swallowed the extra cost. I haven't yet added the extra 1TB drive, but will probably pick it up sometime after Christmas.
Graphics Card: I have had some bad experiences with ATI Radeon cards (and drivers!) in the past, so I decided to give NVidia a go this time. So far, the card is a beast, and the "Windforce" design keeps it nice and cool, without sounding like a jet engine. I have only really tried Borderlands II on it, but with settings on High it kept up fine. My plan is to do some more benchmarking of it this weekend. I'll update the post when I do. I was glad I could pull out the middle HDD cage, however, since the thing is enormous.
Other Thoughts: I did not get an Optical drive, and this nearly bit me when I was bringing the system up. I have an MSDN copy of Win7 Ultimate, and was able to install the ISO to a bootable flash drive, but it apparently does not come with LAN drivers for the new Intel chipset. The ASROCK driver CD had it, so I was able to put the CD in my old laptop, copy the driver to a flash drive, and install it the old-fashioned way. After getting that, I was able to go online and get the ASROCK A-Tuning utility which helped me update all of the other drivers.
I ran MemTest86+ on the "All Cores" setting, and it froze on Test 7. No memory errors, just a hard freeze. My heart sank a bit, but then I Googled it and came across this thread, suggesting there was a bug in the tool. So far I have not gone back and re-tested using the workaround specified here, but have not had any crashes or blue screens yet, so I'm optimistic that everything is working fine. http://forum.canardpc.com/threads/84663-Memtest86-is-freezing-while-running-test-7
The only pieces I have left to get are the storage HDD, the Monitor, and the Headphones/Mic. I'm hoping to either get these as Christmas gifts, or at least buy them after the holidays. I am currently running an ancient (7 year old?) 19" 1280x1024 panel, with a couple of bright red stuck pixels, and horrible color accuracy. I look forward to being amazed all over again when I get the new monitor.