i'd wait for the samsung nc-20.. they are equipped with the via nano, which outperforms the single core atom (n270/n280)..
also, recently nvidia (i think) released a new graphics platform to be used in combination with the single core atom, which will make watching hd movie content possible on the atom platform..! currently i cant even watch (decode) hd content on my dual core atom..
(watch
this for a side-by-side showoff between the via nano reference notebook and one of the atom equipped 'netbooks')
edit: if you can, go for xp.. if you cant, go for windows 7.. skip vista! i'm not a big fan of the software spawning from redmond, but i have to admit, they copied kde/osx pretty well!