I am a big fan of computer gaming and I am wanting to build myself a custom gaming PC. However, I am a complete noob when it comes to building a computer so I have no idea where to start. I tried to select parts myself but I kind of got lost in all the options. I would only like to spend like $3000 or $3500, but If I must i would be willing to spend $4000 all the way up to $5000, although I don't think that will be necessary. Basically what I want is a PC that is easily capable of playing new games for the next few years. It doesn't need to play them on max settings, I just never want to see a game lag again. It's getting extremely annoying. The only thing I have selected was a case. Again, I have no idea what I'm doing so I only picked this case because I thought it looked cool. If it sucks, I'm open to other options.
Now note, this build is complete overkill. An i7 has no real performance boost over an i5 *in gaming*. However, a lot of people speculate that games are going to better utilize an i7 in the near future. But that is all just speculation. Again, there is not really a difference between an i5-4670k and an i7-4770k, *in gaming*. Same goes for the 16gb of RAM; 8gb will do just fine.
I went with SLI GTX 780's by EVGA. I would highly consider waiting until the release of the 780ti which is going to be really soon. You could see a price drop of the 780, the 780ti could have a great price point. I would play the wait and see with this one. Another option to consider would be the R9 series by AMD. Do a little research here, because the GPU is the work-horse of a gaming machine.
I went with a large SSD for the OS and your primary applications and games. If you don't need 500GB (which is complete overkill) go with a 128gb or 256gb version. Also The WD Caviar Black can be replaced for a Caviar Blue to save money.
The PSU is well priced. XFX is a good brand; they're made by Seasonic which is one of the best PSU makers on the market. If you are going to be overclocking or adding watercooling I might suggest going with a little bit bigger of a PSU. You don't want to have it under full load all the time. A little headroom is good.
For the monitors I just went with 144hz 27" 1080p monitors. Also I included the 2013 Deatheradder and Blackwidow (mouse and keyboard respectively) by Razer. You never want to skimp on your "kit" so to speak, because it can make a huge difference in your performance in games.
So this is just what I would do personally. Do some of your own research on these parts and see if they are compatible with your needs. If so, great. If not try swapping them out with something you think is better suited for you.