From Asus webpage on the Eee PC 900
Providing Suitable Environments for Different Needs
To suit differing user requirements, the Eee PC 900 comes in both Microsoft Windows and Linux versions.
The Microsoft Windows version offers more experienced users an enhanced and innovative experience that incorporates Windows Live features like Windows Live Messenger for instant messaging and Windows Live Mail for consolidated email accounts on the user´s desktop. Complementing this is Microsoft Works, which equips the user with numerous office applications to work efficiently.
The Linux version is useful for users who desire task-based icons and an easy point-and-click interface.
Well suited for children or users without any computer experience, it provides a fast boot-up time– ideal for fast Internet access while waiting for public transport, or taking notes on-the-go.
(my bold type) - I wonder if they got Windows at a discount for that