I'm using XFCE in Xubuntu on my work laptop and it's working great. Only problem is the battery monitor plugin. If the battery gets low it pops up a dialog warning me. It seems that this is done in the same thread as the plugin's display as the % remaining figure in the applet doesn't decrease until I OK the dialog box. This becomes a problem when the dialog never appears on top (eg when I'm running rdesktop), or if it is coming up while I'm switching desktops meaning I don't see it. That means I never get the Critical warning, and the percent in the bar isn't updated; then black screen - no battery.
Not sure if this is the place to post this..