If you want the best value for $1500 you should consider a Lenovo or Asus laptop.
I would lean toward a Lenovo W520 for that price. It's a load of features.
You could get by with a refurbished 15" Macbook Pro, but I don't know what you're going to be using the computer for.
Lastly I would advise you from staying away from HP an Dell. The high failure rates and terrible customer service are just not worth it.
Let me know if you have further questions.