The Acer Aspire One netbook comes with the Linplus (customized Linux) Operating System pre-installed, which isn't that good. Linux4one - a modified Ubuntu - offers a good alternative for Linplus.
Linux4One is optimized for the Aspire One & it includes drivers for the Aspire One, with a good interface, derived from the Netbook Remix version.
Itís very easy to install it: just download the ISO, put it on a USB key, plug it into one of USB connectors on the Aspire One, reboot it & press F12 at the 1st boot screen, then choose the USB key as a boot device & install it.
It supports all the onboard devices (including standby mode) & it runs pretty fast (a bit slower as the original Linpus).