Yes, this. Good catch.
Went to the build to modify it to include that, but PCPartPicker hasn't recognized that combo yet, sad times for PPP.
I'll go ahead and make my case on why you should get the i3 or i5 instead of a six core AMD. From my understanding most games today require a minimum of 2 cores, most only take advantage of 2 cores while some can use 4. It would be better to have 2 or 4 more powerful cores than 6 that aren't quite as powerful. Plus I prefer Intel's quality and performance(Keep in mind I DO have an AMD video card, so I'm not THAT biased) not to mention with a z77 chipset board you will be able to take advantage of your intel integrated graphics to provide video encoding support to your dedicated video card with intel quick sync.
Not gonna beat around the bush here, by trying to lump in the i3 and i5 against my recommendation, you are simply posting a brand bias. The i3 and the i5 are very different chips and lumping them together simply makes this Intel vs AMD. IMO the i3 has lost its share in the gaming market (as well as other markets) to AMD's new chips and it will remain this way until Intel releases their new chips where I would expect them to regain control of this market space. For nearly the same price a chip that will at the very least keep up with the i3s and in many cases surpass the i3s, and thats without even counting in the FX chips serious overclock potential. Outside of gaming the FX6300 will floor the i3 in any application that isn't miserably single threaded. Modern games have been being optimized for 4 cores for some time now, not all are, but the bulk are at least attempting to be, thus the days of dual core gaming rigs is coming to a close.
The i5s on the other hand is a completely different story, I will recommend the i5 2500k/3570k over the FX6300 but ONLY WHEN THE BUDGET WARRENTS IT. If on the other hand, the jump to the i5 will mean the difference between purchasing an HD 7850 over an HD 7870 then by no means is it worth it, as the loss of performance between the two graphics cards will be felt much more than the difference between the FX6300 and the i5. Had his budget been about $100 more I may have recommended the i5 2500k (either that or an SSD depending on his preference).
One last thing, the whole "I have an AMD card so I'm not bias" is nearly the tech equivalent to "I don't want black people to live in my neighborhood, but mind you some of my best friends are black, so I'm not racist!". The tech industry is constantly changing and the Price vs Performance sweet spots are ever moving, don't get hung up on stupid bias. A few months ago gaming rigs I recommended swung about 30% AMD and 70% Intel for CPUs, since the release of Trinity and Piledriver, I've found that number to have swung to about 60% AMD and 40% Intel. When Intel releases their next chips, I once again expect it to swing back into Intel's favor.