I'm one of those people stuck between the new MBP 13" and 15" i5. I like the idea of efficient computing and extending battery life as long as possible. I don't game very much, but use productivity apps, light web design, audio editing, word processing. The 13" seems to fit the bill, but the new 15" i5 seems more appealing mainly because of the fact that the new core processors are just that much more future proof than the now aging C2D. I use Handbrake occasionally and the added performance of the i5 would be welcome, but I also have a Win7 desktop to do that with. I don't travel much, so portability isn't a huge concern. My question is mainly geared toward battery life relative to overall system performance when running on Intel HD graphics exclusively (using third party selection software) vs. the 320m. How is the battery life on the Intel HD 15" vs. the 13" 320m and how do they compare in terms of performance? I definitely feel either system would work well for me, it's a matter of preference.