The Macbook Air also has a fan. The base Macbook does not. The base Macbook therefor hits its thermal ceiling pretty much immediately and is suboptimal in hot environments. My girlfriend's overheats all the time.

Frankly, I think the three product lines should be shaped like this:

- Macbook: For price sensitive people. $800-900 to enter the Apple ecosystem.

- Macbook Air: Basically the current MBP with its fixation on power capped by form-factor. (Note: The new Air is heavier than the MBP!)

- Macbook Pro: A portable workstation that doesn't sacrifice everything for form factor. Apple doesn't have one of these right now. For example, prioritizes thermals so that it can sustain max performance instead of the bursty performance of the current MBPs.