You could check out
this list to see some comparisons within your budget.
At the moment, the Acer Aspire V15 Nitro on sale for $799 is the way to go if you want the most performance for your budget.
It has an i7-4710HQ, 8GB RAM, 1TB HDD, Nvidia GTX 860M graphics, and a 15.6" 1920x1080 IPS display, which is pretty crazy for $800. The sale ends in a day or so, though. Anyways, it would play CS:GO on max settings easily.
Other than that, the Asus X550JK comes with Nvidia GTX 850M graphics, which would still have no issues maxing out CS:GO, but it's not far in price under the Acer, has a lower quality build, and TN panel as opposed to the IPS display in the V15 Nitro.
The next good option for less would be the new Lenovo Y40-80...