Very nice rig, a few bits an pieces you COULD have changed but ultimately it will smash it games wise for the next few years IMO.
Very nice choice on the cooler and as for overclocking if you are at stock or close to stock volts you won't affect the life of your gear. My Sandy bridge i5 has been at 4.2 GHz or above since I got it in Feb 2011, and my cooler is not as good as yours, yet it is still going strong and I fully expect will be still going long after it is obsolete for games.
GPUs are built for ocing its even in the drivers, and that is exactly why Intel sell the k series of processors.
Colour me envious.
PS IMO 16gb of ram is loads and I think will be a sweet spot for the next 3 years plus
The reason why I got the k series for mine wasn't to overclock, it came at a higher base clock speed than the regular processor and Amazon had it for £30 less than the regular one.