I haven't been having a lot of luck with stuff recently. My car packed up (in a potentially expensive way1), and yesterday I discovered that the battery in my PowerBook is one of the ones Apple is recalling. Brilliant.
I've filled in the form to get a replacement, so now I just have to wait 4-6 weeks for it to show up. In the meantime, I'm advised to remove the old battery and power the PowerBook from the mains. It's weird though; I've had the laptop and battery for two years without incident (and it shows none of the telltale signs of overheating now), but now that I actually know that there's a tiny chance it might burst into flames, I feel that I should take precautions. However, the probability of something happening hasn't changed, just my knowledge of it.
So I'm going to compromise. I usually just put the PowerBook to sleep for the journey between work and home, but that's obviously not possible with the battery removed. I'm using it without the battery at home and work, but reinserting the battery for the journey, and monitoring the Crumpler bag in which it lurks slightly nervously for signs of smoke or undue warmth.
1 Though _expensive_ seems to be the only possible outcome when cars break down. ↑