My main computer is now an Dell Inspiron Mini 9" netbook which, when hooked up to a mouse, keyboard and monitor, works just fine. Whilst storage is limited to 16GB SSD, I use my old laptop as a big network storage device, and share my media using MediaTomb uPNP, and Rhythmbox's DAAP. Given that ruby and PHP source files don't take up much space, the 16GB is enough for now.
I installed Ubuntu on the Mini9, following the excellent guides at ubuntumini.com, and for a few months used Ubuntu's default Gnome desktop setup. Over time, though, and despite having upgraded the memory to 2GB, I found the computer sometimes grinding to a halt under the weight of a few apps and lots of desktop composition effects. This was especially true of Firefox.
Last week, I decided to look into ways of speeding up the machine, and tried out XFCE. XFCE is a desktop environment built on the GTK libraries that is specifically designed for speed. Using XFCE, the little netook now powers through through apps, and I've not seen the greyed-out hung windows for a while. Although it may not have the glossy Compiz effects of Gnome, I find the look of XFCE much easier to work with - The font rendering, in particular, seems sharper, which makes browsing code easier on the eyes.
So, for now I've abandoned Gnome for XFCE, and everything seems to be a lot smoother. There are some things I miss from Gnome, one of those being that XFCE's default file browser (Thunar) cannot browse networks or external locations (e.g. ssh://) in the same way Nautilus can, but this can be overcome by running Nautilus in XFCE:
So, should your netbook be grinding under the weight of Gnome or KDE, give XFCE a try. The full Ubuntu XFCE ([xubuntu](http://www.xubuntu.org/)) can be installed on Ubuntu using:
sh$ sudo aptitude install xubuntu-desktop```
You can also install just the Xfce desktop (without additional Xubuntu niceties) using:
sh$ sudo aptitude install xfce4