It wasn't that high end, all together, including a 22" monitor, speakers, keyboard/mouse, and shipping was less than $1100.
Mostly I plan to play games that my PS3 struggled so much with that I couldn't finish them or did only with great patience and many crashes/reloads, games like Deus Ex (the new one), Fallout New Vegas, Skyrim. Also games that were fun but he graphics sucked on PS3 like GTA 5 (I wanted to do the story again but there are points where it's hard to see because of the graphics quality). Plus I'm excited to play things like Fallout and Skyrim with mods. Also I play a lot of sim games like Civilization, the Sims, Kerbal Space Program, and Cities Skylines that played okay on low graphics settings on my Mac, but are going to look incredible with a proper video card.
I also plan on eventually getting an SSD too, I have one in my MacBook Air and it's phenomenal. It would have added an extra $250 to the cost of the build, and I for one don't need it yet and for two know I can get an aftermarket one for way cheaper when the time does come, probably in the fall.