Here's the deal. I am looking for a light laptop, with very good build quality (sturdy), a quality screen 13" and above (good color and contrast for movies), and battery at least 4 hours for browsing at 80% brightness. Budget is $800. Is such a laptop really so hard to find ?
Well, the demands for Starcraft and that of AutoCad are pretty different. You can run SC2 on low on the integrated Intel card, but i don't think AutoCad would run well on the same setup. If you think having a high res screen (higher than 1366 x768) is important, then i think your only choice at your price range is the Dell XPS 15. If having a 1366 x 768 screen is ok, then there's a few choices:
For 13", there's the Acer 3830TG (Intel i5, Nvidia 540M)
For 14", there's the Samsung QX411 (i5, Nvidia 525M)
For 15", there's the Asus N53 or A53 (i5/7, Nvidia 540M)