If you want a light, but high-performing laptop, I'd suggest this - (http://www.amazon.com/MSI-GE60-Apache-Pro-003-15-6-Inch/dp/B00IMTQ3UW/ref=sr_1_2?ie=UTF8&qid=1405980349&sr=8-2&keywords=860m+laptop) -$1,082.99 and it only weighs 5.3lbs.
It can run most modern games on high settings and it's a fairly lightweight option. Another option that's even lighter is the MSI GS60 Ghost (http://www.newegg.com/Product/Product.aspx?Item=N82E16834152566R&cm_re=860m-_-34-152-566R-_-Product) - $1,419.99 and it weighs 4.3lbs. This option is a bit more expensive, but it comes with an SSD for fast boot times.
The only issue with thinner and lighter laptops is cooling. Generally, these types of laptops may face overheating issues because of their...