Boston Power has created a new line of Lithium-Ion batteries dubbed the Sonatas, batteries that deliver an average of four hours of laptop use per charge. In addition to that, they also don't show a degradation of charges after a long period of time, meaning they'll hold that 4-hour charge as well three years down the road as they do right out of the box.
And now HP is the first company to offer these sweet batteries in their notebooks as of early next year. They should be about $20-$30 to upgrade to from a regular battery, which sounds like a pretty great deal to us. Better batteries make laptops happy.