Laptops + physics

I'm not sure if this is an issue for everybody, but battery life is a serious issue with me and my laptop. This is compounded by the facts that:

The PowerBook's battery life isn't that great. About 3 hours max if i turn my screen brightness is at the lowest and all I'm doing is writing text/code.
Sockets are hard to come by at Tech-Ed.

So i'm usually always paying attention to what my battery life is at and what I'm going to need to do to make sure that I can stay up. However, there's a bit of an issue with this system. At one moment I might look and see that I have 1 hour left, then a couple of minutes later i look and I'm down to 20 minutes. What happened!!! Right about that time I start realizing that my ... um... upper leg area is starting to burn. I open up top and what do I find? Some process like iChat or Entourage has starting sucking up 100% CPU for a few minutes straight. I quickly try to figure out why and stop the offending process, but I've already ended up losing like 20+ minutes that I could have been working.

I know about graphical views of battery life (i use iPulse but don't like how much CPU it uses) but I'm unsatisfied with them. They're good at showing you your current velocity, i.e. at this rate how long till your battery will be gone. However, they're really bad at telling you when you've suddenly started sucking up an unreasonable amount of power. What I'd like would be some kind of accelerometer that would tell me that (even though I have 2/3s of my battery available) I'm draining at really rapid rate.

Any tips/tricks on making sure you can really maximize battery life?