I received an Acer Aspire One netbook a few weeks ago from Acer through a special program (http://educationaltechnologyguy.blogspot.com/2009/06/acer-one-netbook-review.html) and I love it. Mine has a 6 cell battery and lasts for over 6 hours with Google Chrome and OpenOffice running. I am getting used to the smaller keyboard and use it when I teach at other sites (paramedic, EMT, and CPR classes).
What I really love about it is it's size. It is small and lite, but still easy to use. My classroom at the high school has the small desks with the side desktop, so a netbook fits much better than a full size laptop. I've been able to use every web page, web application, and software that my students would use in my class without any problems and it runs faster than many of the desktops at the school. I'm working on getting funding to purchase a classroom set of them for next year because they are so useful. I want to be able to give every student a computer to use in my room. The netbooks would also allow us to bring them outside when we do experiments.
I am pushing netbooks vs. full size laptops at the school because of cost and size. They do everything the students need them to do.