The UL80 series of Asus laptops was a thin-and-light version of laptop in their many line-ups of offerings.  The UL80 mostly consist of ULV Core 2 Duo processors, with the newest/eventual models equipping with 1st generation Core i3 ULV processors (i3-330UM version).  While this is an older model laptop (it is currently succeeded by U41JF form Asus), you can occasionally find some decent deal on the UL80JT model, which is currently hovering around the price range of low $600 to high $680.

Some surprising perk from the $600 ish thin laptop is a discrete GPU with the Nvidia NV 425M with 1GB of DDR3 video RAM along with Nvidia Optimus technology so you can switch to the integrated Intel HD graphics to save on battery life while you're not intensive graphical work.  Additional nice perk includes the 2 year warranty along with the 1 year accidental damage warranty.