Honestly my personal recomendation based on what i would do. Look for or wait a bit for the new asus g750 with 860m refurbished for $999. I think it was just yesterday newegg had them. The 860m is like i said way more powerful than the 765m. But if you cant wait, cant find a 860m in your price range, id go with the 765m. YOu'll still get high settings on most games (which on a lapotp screen is still great, i was happy with medium settings). Asus build quality in their g750 series is just superb. But it is a big 17" that weighs 10lbs. But if you do go any slimmer, your getting a 750m which is a huge downgrade, and then you have to deal with a scortching laptop, high fan noise, and thermal throttling. If you find a good backpack, i use a targus breifcase thing, the portability is just as good as a light 15", but you'll really appreciate the 17" screen realastate once you have it.
I would stay clear of hp, dell, samsung, or any other slim laptop with a graphics card, more hastle than it is a pleasure to deal/work with. Asus makes a slim i7 quad core but those are still around the $1200 mark. Theres the lenovo notebook for $800ish which gives you sli 755m and an i7. But mediocre build quality, poor keyboard and battery, and horrible heat. So even though its larger the asus with 765m for $900 beats out anything else even close to it. Next best would be the asus with 860m which i would recomend to anybody looking for a laptop. I only went with 870m as the graphics card for rendering is a vast improvement, but i had and loved my 860m version. It was just a screaming gaming card. And i still liked my 765m model as well but then the 860m upgrade came out while my 765m was still in 30 return policy so for same price that was a no brainer upgrade.
But i can tell you even with the asus with 765m you will not be disapointed, not sure about the refurbished deal being used and such, but if it was that bad you can always return it and try again. Neweggs good on that end.