Looks like a nice build. Yes, RAM is cheap so we all tend to load up on it.
Truth is, you'd be hard pressed to use more than 4.5GB under any circumstances, so 8GB is more than you'll need for years. But hey, who am I to talk with 16GB I can't use. I bought it, because I couldn't resist the price for 1600MHz Corsair Vengeance, for $74.99.
Oh, and to answer your earlier question. You will see, feel, perceive, absolutely no difference between 8GB, 12GB, or 16GB of memory. You will also never be able to detect the difference between 1600MHz, 1866MHz, or 2100MHz, without the aid of benchmarking apps.
I'm running the same Mushkin SSD you intend to buy. If you want it to run at or slightly above it's rated specs, be certain to use your motherboard's native Intel SATA III ports.
Thanks. Regarding the RAM, it's what I already knew, but helped me convince myself that 12GB is more than enough!
I notice you use the i7 3930k w/ H100 cooler, any input on pros/cons of those coolers, or whether its worth the upgrade from my i5 choice to the i7 3930k? Bearing in mind that I use my computer almost exclusively for gaming, some graphic design occasionally (just basic Photoshop, minor animations), and as a part of my music/movie entertainment system.
Money is not really any object, $300 extra on this build just means $300 less wasted on weed/vodka that paycheck... But I still don't want to be throwing money at parts of my computer that I'll never see a return on investment from. I'm already investing more than necessary just because I enjoy enthusiast builds and as much futureproofing as I need.