@ NewEgg website: Lenovo IdeaPad Y560 15" notebook $700
Core i5 480M 2.66GHz CPU, 4GB RAM, 500GB HDD 15.6" 1366x768 LCD w/ HD 5730 graphics.
It meets all your requirements except the battery goal of 3 hrs. That HD 5730 graphics card isn't switchable when not gaming. Lenovo IdeaPad Y560 Notebook
this reviewed model had a different CPU (quad core) and faster 7200 rpm HDD but the review should be valid for that NewEgg model as well.