RE: 16gb of RAM
Unless I've missed it, one thing that hasn't been mentioned in regards to getting 16gb is the current price of memory. RAM is expensive at the moment (my eyes almost popped out of my head when saw that Samsung Green RAM has almost doubled in price in the last year or so). My advice would be to get 8gb, which is the so called "sweet spot" for gaming builds at the moment, and leave room for future expansion.
As Hyburnate said, do you need an OS?
As for the i7, if the build is going to be primarily used for gaming then an i5 would just as good... in certain games the i7 will perform better but not by anything close to a significant margin. I'm speaking for experience when I say that you should give serious thought as to whether and i7 is worth the money, whether you'll really need the features unique to the i7, whether the money can be better spent elsewhere and finally, whether (wow, I'm really using that word a lot... it must be the weather) you're falling into the "moar powar, bigger numbers" trap. I almost did until I realised that an i7 just would not benefit me enough to justify the expense.
My final piece of advise is get a quality PSU. Don't get more power than you'll need, so take into account whether you'll be adding a second graphics card or watercooling to the rig in the future. We can spec you a better PSU if we know what your requirements are. One other small thing to think about when getting a PSU if you choose to select one yourself is the new Intel 4-series processors use a low power state called C7. A small number of PSU's aren't compatible with C7. It's not really a big deal but it'd be silly to not go with a C7 compatible PSU.