This thread and a few others inspired me to finally OC my aging I7 920... bought a Cooler Master Hyper 212 Plus (so inexpensive!), and am at 3.6GHz stable at the moment (about 42 idle, 65-68 full load). Have a feeling 4GHz will be a little too hot, but I'm going to mess with it and see if I can do it. I'm only running 1 fan on the 212 at the moment, but will add another later this week. No issues whatsoever so far, though, which has been nice. It's made this older rig fun to tinker around with, and if something goes wrong, not too big of a deal.
The CM 212 install was a bit of a PITA, though. While I get why that backplate is needed, I had to completely remove the mobo from my case to get access to a couple of the mounting holes. Took way longer than I was expecting, but once that was done, the rest of the install was simple. For the price and performance (I was overheating previously on the stock cooler at only 3.2GHz under load), I suppose I really shouldn't complain.
New RAM incoming too. Still on 6GB DDR 1333. 8GB of DDR 1600 arriving tomorrow. Nice thing about our household is that my wife gets the hand-me-downs, so when I upgrade, so does she.
Thanks again for this thread. Some of your guys' builds are just fantastic, and you can tell a lot of thought went into them.