What is the best laptop for 2000-2500 USD?

I am looking for a laptop that is relatively portable (will carry around in a backpack a lot) with the best processor, screen resolution, graphics card, durability and cooling system. I would prefer it to be 15.6" and not too flashy. I will have $2500 to spend and I will lose anything I don't spend. That means a $2500 laptop with cash and warranty would be ideal. If it is a little less I can also get a monitor keyboard and mouse to balance it out.