Out of curiosity, what browser do you use? I've found on both my Rev. C MB Air and the new white unibody MB that I purchased this past week that when on battery, when I fire up Firefox, my battery burns through like crazy. However, as soon as I close it, and start up Safari instead, my "time remaining" jumps back up, often by at least 1hr 45min to 2hrs, and I actually do get a lot more runtime. Since noticing this, I've played around with using each computer with Firefox running in the background, then Safari, and using Safari gets me far more runtime very single time, especially on the new white Unibody. I've gotten up to 8.5 hours out of use between charges using exclusively Safari, but using Firefox the most I can hit is around 4.5 to 5. With my Air, Safari will get me 4.5 hours usage max, but Firefox will drop that under 3. The Air is running 10.5.8 (Leopard), and the Unibody is running 10.6.2 (Snow Leopard). Has anyone else noticed anything similar to this?