This is going to be my first serious gaming PC. I have thought things through to my best of knowledge and now im asking for tips here. If you have anything to say whether its good job or you should do this. Now my price limit is $2, 500 and I managed to go lower. So here she goes....
drop down to an i5-3570K build. pointless to grab an i7, much less SB-E CPUs for gaming, unless you're also doing stuffs like rendering, multiple VMs, or other professional work/hobby.
unless you're aiming for looks and willing to invest in the time and money and this is really you're first gaming PC, go for air cooling. custom liquid cooling requires regular maintenance, one that you'll have a better advantage of building one yourself due to familiarity. reliable all in one close loops are horrible for the price compared to air cooling.
2x4gb 1600mhz. the most you'll need for a PC solely for gaming.
if you followed my advice so far, you may have saved up a bit and be able to spend on a 670 or a 7970.
unless you're desperate for more FPS in the VERY few games that struggles to reach 60 fps @1080p at max settings, stick with one GPU if you're using one monitor. 2 if you're using 3 monitors.
try to grab a 750W PSU at most for a dual GPU build, 550-600W for a single GPU, preferably from corsair, antec or seasonic.
with your budget, you should be able to grab a 128gb SSD, much more so if you followed my advice, except on the GPU maybe .
that should knock off several hundreds off the final price while still maintaining the same performance in gaming from your initial build. any cheaper than that, and you're looking on building your own. or at least buy the parts separately and find a shop or anyone to build it for $100 or less, at worst.
what your build would priced at, give or take a $100, if you're looking for someone else to build it. if you're using a single monitor, consider a single 670, and buy another later. that should save you $350+. or buy two 660ti's now for a single monitor if adding another later is too much hassle, and save up $180 or so. mind you, i'm actually lazy, so there maybe better deals than what i just conjured up out there.
^+1 on all the points. That rig is very overkill for what your after.
You can build a fairly top of the line gaming rig for about $1500 if you don't get the bells and whistles, so I imagine with a prebuilt you could get a $1700 rig thats will do the same.