I have been trying out several linux distributions on my Aspire One to find one that suites the machine best, I have tried everything, including a copy of PCBSD that was well "less than successful".
The two top runners are currently Fedora 10 (beta) and Ubuntu 8.10 (beta).
First a warning, Beta software is not for everybody, you can end up with a dead machine if you hit an issue with an update, and have to know how to recover your machine when that happens. You also have to have a good set of backups.
There is a superb tool called remastersys that creates boot able backups of not just your data, but your entire operating system, which I use in conjunction with an external FAT formatted USB drive.
One thing I have found is that trying to find a distro that supports the very recent hardware and chipsets found inside the Aspire One is hard, and I have narrowed my evaluations to those distros shipping the brand new 2.6.27 kernel or later, as that is the only one that seems to support the chipsets out of the box. I also need to have networkmanager 0.7, to support my Mobile USB broadband modem (a Huawei 169G).
I was using Ubuntu at first but needed to change to a RPM/YUM based system due to us using Centos 5 everywhere at work, and since I am building code that needs to be run and installed in that enviroment, the differences in the package managers was just too great for me to be comfortable with. (Yes I write software on my Aspire netbook, its quite capable of it, I was very surprised at how well Eclipse performs on this platform, almost as fast as my 2008 macbook).
Installation of both distros was relatively easy, I used unetbootin to create a bootable 1G USB thumbdrive directly from the distributed ISO's and booted from that, I did not notice any issues with installation of either distro. Out of the box Fedora was slightly better in this respect, with a few caveats. Choose the gnome distros for each, as I have found that the newer KDE setups are somewhat less functional, in particular current KDE incarnations (4.1+) seem to have issues with saving settings.
Ubunto produced the more complete setup here, but only after I deleted the /etc/X11/xorg.conf file and allowed the new xorg 7.4 system to work its magic with configless boots.
glxgears turned in a performance of about 350 fps, which is fast enough to enable compiz desktop effects, however since that is just eye-candy its debatable whether it is worth enabling it on a device of this class. A minor irritation was that in order to support multiple screens, the screen resolution app has to create an xorg.conf with a virtual screen that encompasses both physical screens, and it initially gets it wrong which means that the external monitor resolution is low until you hand edit it to up the required size, I just doubled the dimensions in both directions and rebooted and was then able to select the 1280x1024 res I was looking for on my monitor.
Fedora was a mixed bag, it again needed the delete my xorg.conf trick, but try as I might I could not get it to properly support an external monitor at a reasonable resolution. However the performance of the driver in glxgears is significantly better, getting 550-600 fps. Im still trying to determine the reasons for this performance difference.
Due to the inclusion of networkmanager 0.7 in both distros, wireless was a doddle, both wifi and usb modem worked out of the box, however both distros suffered from the same issues re DHCP and wifi performance.
Every now and then they refused to acquire either a wired or wireless ip address due to dhcp timeouts, rebooting the machine seemed to clear the problem. The wifi is using the new ath5k driver for the Atheros chipset in both cases, and I have found that this driver seems to effect the sensitivity of of the wifi, with far lower signal strengths than under the older madwifi driver, and frequent dropouts and stalls.
Also under the madwifi driver there where a set of sysctls that would enable the wifi led which dont work on the ath5k driver, and I have not found any substitutes. The driver binds to the led_class module, and looking at the source has functions for enabling/disabling this mode, but I cant find any documentation on how to enable it.
Ubuntu has working suspend and resume, the sound sometimes does not restore properly coming out of sleep of hibernate but that is a minor annoyance, on Fedora both modes where a bust, resulting in a locked up machine requiring a hard reset.
I must admit my needs are probably different from average, I need to enable a full local LAMP stack and software development tools (yes it runs fine, and no the machine is not slow after doing so). The Aspire has dual 1.6Ghz cores, up to 1.5G of ram and a 120G HDD so its quite capable of handling this load. It should be noted that the spec of the machine is amost identical to the perfomance of an instance running on the Amazon EC2 cluster (1.6Ghz, 1.6G Ram, 160G HDD).
With Ubuntu setting up the stack was hard, on fedora this was a Breeze, Fedora even has a full Eclipse 3.4.x install in the repository, and has installable packages for eclipse PDT, subclipse and Xdebug. So my usual fight to get a working PHP dev enviroment working was eliminated.
I was able to setup up the entire machine for running our web app, including checking out the code from our subversion repository in under 30 mins, vs the 3-4 hour battle that I had with ubuntu. The Fedora packages even setup the correct SVN provider interfaces for subclipse which really impressed me.
I had some trouble setting up netbeans on Fedora, but mainly because it could not find the JRE directory, once that was sorted out, it installed fine. I tend to use Eclipse for PHP development, and Netbeans for C++ development as I have never really got on with the Eclipse CDT.
Ubuntu is defiantly the more polished distro for general use, my specialised needs tend to lean me towards Fedora where im willing to put up with the shortcomings, I also like the faster more responsive feel to the fedora distro.
One final tip, if you are playing with beta software and hit issues, then engage with the community around the distro, they are normaly very responsive, and make sure that any problems you find are submitted as bug tickets, or they will never get fixed. Dont just sit back and wait for somebody else to report the problems...