Next year I am going in for Industrial Design at Iowa State University. I am going to go for either the high-end 15 inch or the 17 inch. I have a couple concerns though: 1. Which one gets better battery life, I know they are both advertised as 7 hours, but there MUST be a difference? 2. Does anyone find the 17 inch a little hard to carry around? The reason the 17 inch interests me is because then I won't need an external monitor. 3. Does anyone ever find the 15 inch hard to use without an external monitor on a desk? Is it too small to use? 4. What is the realistic battery life people are getting from these computers? Is it 9 hours like Anantech stated?