I have jumped on the weensy netbook bandwagon and purchased an ASUS Eee PC 901. It is teensy and black and is running a spare XP license I had left over from when I upgraded my now massive by comparison laptop to Vista. It is wonderful! It is quick, small, and lasts upwards of 8 hours on a charge. With the wireless on, even! I'm using it primarily for class - taking notes and pulling up materials on Westlaw and Lexis. I'm also using it for email and my calendar, courtesy of (get this!) Office 2007, which runs surprisingly smoothly on the tiny SSD hard drive. It took some tweaking to get everything running smoothly, but once I got it all worked out, the Eee became absolutely perfect. I've even gotten used to its tiny keyboard - to the point where typing on my behemoth is now a little uncomfortable.
All that said, I cannot recommend the Eee line of netbooks to everyone. They have a funky hard drive situation, with a tiny (4GB) main drive that has fast write speeds and a larger (16GB) data drive with much slower write speeds. The write speeds on the slow drive make certain operations tricky. XP often writes back to the drive, so XP and its programs need to be on the faster drive in order to work smoothly. This limits what you can do with the Eee. If you really know XP and know how to do it, you can shrink your Windows installation and move installer caches off to the data drive so you have plenty of space, but it takes work. I have no idea whether the XP version of the 901 comes with these sorts of modifications to the operating system. The version I bought came with a dumbed-down Linux distro that was absolutely useless for what I wanted to do with the machine. I researched the machine's limitations and knew what I was getting into before buying. I recommend that anyone interested in getting an Eee (or any netbook for that matter) to do the same.
Anyway. I also got a Sony Reader a while ago. I wanted an e-paper device for reading my law casebooks, which, through an arrangement with the publishers, I have made a practice of scanning for use on my laptop since starting law school. I was torn between the Kindle and the Reader, and finally decided on the Reader for two main reasons: 1) I did not need the Kindle's wireless feature, and 2) the Sony Reader is made of metal, rather than the Kindle's plastic. The Reader was also $100 less than the Kindle at the time.
And I also love my Reader. I have not actually purchased any books for it from Sony's e-book store, which has a limited selection, but I have managed to use my textbooks on it with great success. Sony recently pushed a firmware update for the Reader which greatly improved PDF handling and adds compatibility for the emerging, ISO-standard-aspiring IDPF .epub format. There are lots of stores out there on the Internets that sell .epub format books.
So now for school I have my Eee PC 901 and my Sony Reader. Both of which are positively lilliputian and fit into a tiny bag. No more big heavy backpack for me!