If you have an iPad and you leave your house in the morning, you can be gone all day, use the thing for 10 hours, and come back home never carrying anything other than that thin device.

Laptops aren't quite there, but close. If I leave my house in the morning with my Macbook Air fully charged, I can get about 7 hours out of it. Provided I eat lunch and am not in front of it for the full seven hours, it lasts a workday, and I don't need to carry a charger. But that is not enough. I want to be able to perform processor intensive activity all day like watching video, and then take it with me to a coffee shop or wherever after work before I go home and still not have to plug in.

Currently, the great battery life of a tablet comes from the utilization of the power-sipping ARM chip. ARM architecture powers mobile, but not laptops. Intel is working on low power solutions for laptops, and there is talk of Apple moving the ARM architecture into their Macbook Air line (though this is still speculation at this point).

Either way, the trend is clear, and we're going to get improved battery life on all of our mobile tech through a combination of processor architecture and battery improvements.

I already have a hard and fast rule about buying my next laptop. I will not ever purchase another one until the laptop sports a full Retina quality display, and battery life over 10 hours. If it doesn't, there's just no use-case incentive for me to get another. I don't believe I will have to wait too long. Maybe a year, -two max.