These are essential pieces of software for the asus eeepc, there dead easy to get and set-up, it has to be said they help to make this little machine a great "wardriving" tool.

Tweakeee
http://www.infinitedesigns.org/eeepc/tweakeee_0.4-0.i386.deb
contains loads of software repositories, and a resource for Econtroll an over clocking program where you can set the fan to stop your machine over heating the way it does.

BackTrack 3
http://www.remote-exploit.org/cgi-bin/fileget?version=bt3-usb
this is a usb or sdhc card mountable operating system, it contains all the wardriving software and security maintanence, your ever gonna need. plus it has some really cool graphics.

emeditor
(use tweakeee to obtain)
after installing the full kde i decided i can do everything i want from easymode but i wanted to change those gawdy fisher price icons, this program made it take seconds.