This is new, just started this month:
Usually it would last until 0%. For a few days it had been shutting off at around 4%. Last night it shut off at 5%... really hope tomorrow night it's not 6% and so on :/
It doesn't just go to sleep when this happens, it actually shuts off.
I bought this MacBook around August, 2008.
My battery is OK according to system profiler. And its health is at 85% according to iStat Pro widget. It's at 703 cycles and 3 years of using it 24/7 as my main computer.
OS 10.6.8, all up to date.