(This one is for Larry and Martin.)
Chris’s iBook battery had started to age out, and it was time to replace it. The stock Apple battery is 61 watt-hours, for $129. This yields ~6 hours of runtime when new.
However, from my time with Nestor at Argonne, I knew of a company called Newer Tech. (Pun intended.) They make a line of high-quality batteries with higher capacities than the stock Apple parts, and the prices tend to match Apple’s. So here’s their offering:

(Image is a link to the product page)
Looks the same, but 74 watt-hours for the same price. Kind of a no-brainer, eh? They also have a 60W-H, but for the difference in price its better to get the 74 IMHO. The new unit is producing ridiculously long runtimes on the iBook, much to my 3-hours-on-a-good-day-MBP envy.
What’s more, they include free recycling of your old battery, with prepaid shipping. I really like that.
Highly recommended.