I took my 17" powerbook to the local Apple Store, where they let me test a new battery before buying it. I wanted to see if the battery (replaceable) was dead, or if the charging circuitry (not replaceable) was dead; thankfully, it turns out it was the battery. I bought the tester battery (new, but returned because it was the "wrong size" -- it pays to read the labelling, people!) at a $50 discount. Not bad -- free help at the Genius Bar plus a discount on a new battery. My wife has the laptop now, and just loves it. It's an upgrade from her G3 iBook. It is, in her words, "lighter, faster, bigger!"

The "d" key still double-types sometimes, but she's not complained about it. I don't have a solution, yet, but I'm still looking for one.