I didn't have a lot of cash to be able to do this with, so my initial build was with a single GPU. I absolutely love how powerful this PC is, considering I was able to watch and wait for the prices to drop down to predicted low levels via this website, allowing me to spend considerably less overall than I would have if I had bought everything all at the same time.
I was able to stretch out buying the components over the span of just a couple of weeks as I waited for the prices to drop on each one. In short, I was able to save roughly 250 bucks on my initial build just by ensuring that I purchase all of my parts at their lowest predicted prices.
After about 5 months, I had enough cash saved up to get a 2nd GTX 970, and I just purchased it as well, again, at the lowest predicted price. I can't wait to get it in, and see how this super low priced, high end gaming rig does with these dual 970's!