Until recently I used icewm as my window manager, but for reasons described in (excessive) detail in another question I have changed to fluxbox. I have no criticisms of fluxbox, the user interface is uncluttered and easily configurable, but one feature of icewm which I particularly miss is the CPU and network monitors, which sat in the system tray and gave  a compact but informative display of recent activity.

Can anyone recommend standalone programs that perform a similar function?