Toshiba Mini NB205 (PLL20U-00201D) Netbook

Although this Toshiba NB205 is so small and light that you can fit it in your day-bag, its keyboard is almost full size, and it has a pretty good memory.  I use mine to juggle the files from 3 freelance jobs, store my itunes and keep my image library.  In fact, this tiny computer has a larger memory than the laptop I bought in 2005.  By far the most impressive thing about this netbook, however, is the battery - which lasts for a stunning 9 hours.  You charge it overnight like a phone, then take it with you all day - sit in a cafe, work on the train or the bus.  It's like technology, but without most of the hassle. 
The main drawback that I can find for the Toshiba NB205 is the fact that the keyboard takes some getting used to.  The computer's tiny frame means it is easy to sweep the mouse pad with the palm of your hand by mistake, while you type. But after a few days of use, I got used to a slightly new style of typing - as with any new keyboard. 
Personally, I do not use the Toshiba NB205 for writing up long documents.  For that, I return to my old laptop (even though it seems like a creaky old dinosaur in  comparison, and has to be plugged into the wall), because the screen is so much larger. However, for browsing, emailing, and writing notes throughout the day, the Toshiba netbook NB205 is perfect.  If possible, I would recomend using the Toshiba NB205 as a portable computer for working on during the day, and a desk top or larger laptop for finishing long documents when you can stay in one place for a long stretch of time. 
Having said that, if you don't have the luxury of access to two computers, I would advise investing in the Toshiba NB205.  It is cheap and reliable, and that long life battery means it is truly mobile.