Most Netbooks aren't suitable to run "heavy" Operating Systems like Windows Vista, or XP. That's the reason why many users are installing a Linux distro onto their Netbook & some manufacturers like ASUS & Acer do offer their Netbooks with Linux pre-installed. Tux Radar did test some popular Linux distros.
Tux Radars test Netbook was an Eee PC 701, featuring 4GB of internal storage, 512MB RAM and a 900MHz Celeron processor. Three of the Linux distros we tested (namely, Xandros, EeeXubuntu and Pupeee) are optimised for Eee PCs, but each of these should also run on other netbooks. The fourth distro on test meanwhile, gOS, is the default one installed on Everest netbooks.
Acording to Tux Radar "EeeXubuntu, best nails down the essence of what makes a netbook distro change a good idea."