A few weeks ago I bought my first netbook, an Acer Aspire One AO751h. Today these are selling at NewEgg and elsewhere for under $300, but if you intend to run Linux today you should try a different model.
** Update June 2011: The AO751h really sucks at running Linux. I continued having the issue where it would not resume from suspend every time, sometimes wireless would not re-activate, etc. Eventually I put Windows back on it and gave it to my brother. **
I wanted a netbook because it would be light enough to take "everywhere" and due to cost. Ultra-light notebook computers are still over $1000 which is more than I wanted to spend. I chose the AO751h because the case comes in various non-generic colors (I chose blue), it has a nice big keyboard, long battery life, and the screen is 11.6 inches with a resolution of 1366x768. The large hard drive (250 GB) allowed me to double- and triple-boot while I tested various Linux distributions. This netbook is great for web browsing, running vim/emacs, SSH, git, and Remote Desktop. I bought the Windows Vista version of this netbook in order to get the included 2 GB of RAM. The AO751h includes a 6-cell battery and lies flat on the table, unlike some of the netbooks that have an ugly battery sticking out the bottom that raises the back of the netbook up. I need proper ergonomic keyboard angle to help avoid wrist problems. I plan to do a lot of typing on this computer.
Sadly, the AO751h and Ubuntu are not yet a match made in heaven. After some struggle, I did manage to get a usable Ubuntu 9.04 system, Enough quirks remain that I continue to dual-boot with Windows. Windows Vista was very slow on this hardware, so I replaced Vista with Windows XP which runs very well.
Here is the Ubuntu wiki page for this system:
There are two major Ubuntu compatibility issues with this hardware that require tweaking... the video resolution and Suspend/Resume. Wireless works out of the box although sometimes the device takes over 15 seconds to re-activate after Resume (and occasionaly wireless never comes back and I have to reboot). The function keys for brightness do not work in a fresh install but seem to work ok after installing the psb-kernel-source package for the Intel Poulsbo (GMA 500) graphics.
Detailed hardware info (including lspci output) is at the bottom of this post.