The one thing I dislike about my Acer Aspire One Netbook is the anaemic battery life. My unit came with a 3-Cell 2200mAh battery and all I could get was 2 to 2 1/2 hours out of it so I bought a new 9-Cell 7800mAh battery on eBay and now look at this: more than 9 hours!!!
Of course the new battery is much larger then the original one (434g instead of 162g).
The way the battery is made, it tilts the Netbook just a little bit. You can also use the battery to hold the Netbook firmly.
