Another cool tweak for your menus. This adds a bit of transparency to your menus, drop down menus, tooltips, notifications and a few other small things. It gives them a clean look with just a hint of transparency.
In CompizConfig Settings Manager, under General Options, in the Opacity settings:
Select edit and copy this into the pop up window:
((type=Menu | PopupMenu | DropdownMenu | Tooltip | Notification | Combo | Dnd | name=sun-awt-X11-XWindowPeer) | (type=Normal & override_redirect=1)) & !(name=sun-awt-X11-XFramePeer | name=sun-awt-X11-XDialogPeer | name=gnome-screensaver)
I set the Opacity window values at 96-98, giving it a nice clean look. You can set it to whatever you like. I think everyone should check this tweak out, it really pretties up the desktop.