More power means .. well, more power and therefore more cooling, less battery life and more weight. (Don't forget the charger, 120W one is a lot heavier than a 45W or something.)
Maybe you want to explain the exact usage for the device? Is it something that lives in a drawer? Does it have to be carried around every day?
If you do accounting work - Do you need a numberpad included in the laptop or do you like to use a dockingstation at your desk. Please consider that also ! Perhaps a Lenovo E570 is more suited with that extra numberkeys.
Battery life is important but so is performance. I need something that is easy to travel with if i want to work outside the office or when i travel. it will not be a daily driver but it will be taken when traveling. numpad would be nice but not necessary(normally numpad makes the laptop bigger in size). WIll be using my desktop a lot more than laptop.
Honestly my lenovo is a dual core and it does amazingly well for what it is. As I said its as good as my desktop for what I do. With that, the cooling is so good on it it stays at its 3.2GHZ turbo.