Since you want battery life, here's a listing of high battery life laptops (it's a little old, Aug 2012): »blog.laptopmag.com/all-day-stron ··· otebooks
How much on-battery run time are you looking for anyway? 8+ hours? More, less? Since you can get an i5 within your price range I wouldn't look for an i3 or an AMD, personally. The rest of your requirements look good (15ish inch screen, intel CPU). How much RAM and drive space are you looking for? For me I have a file server so individual drive capacity is largely irrelevant.