They are advertised at around 4 hr lifetimes -- how come I'm not getting the same length on my laptop. Right now I get about 2 hours and 10 minutes without a battery.
it's 4 hrs if all you do is surf the net and type word documents. If you watch movies or run a bunch of apps at the same time then the battery life is much less than the advertised 4 hours. I used a centrino laptop for browsing the web only and it did last 4 hours.
I've got a Dell inspiron with centrino and it gets me about 4.5 hours of life during normal use. Like stated previously, other things like video intensive or cpu intensive applications will drain it faster. burning cd's takes up a lot I've found.
The crappy thing about the batteries is that not only do they have short lives, but then they stop working after about a year or two, so you have to spend 100 to get a new one. Normally, after a year, they are not covered under the warranty (with Gateway at least).