Tint2 is a lightweight panel/taskbar intentionally made for Openbox3, but should also work with other window managers such as Gnome.
* panel with taskbar, systray, clock and battery status
* easy to customize : color/transparency on font, icon, border and background
* pager like capability : send task from one workspace to another, switch workspace
* multi-monitor capability : one panel per monitor, show task from current monitor
* customize mouse event
* window manager's menu
Tint2 is very configurable, like I told you above, but this is done via config files meaning you have to use a text editor for customizing basically... everything, which might confuse 'non-geeks', but we will cover a way to do all the configuring via a GUI tool, so keep reading.