I like Keyboard instead of Mouse. Keyboard is a much faster method once you memorize the commands.

Gnome
Switch workspace: Ctrl+Alt+Up/Down/Left/Right
Switch between windows: Alt+Tab
Gnome Menu: Alt+F1
Close Window: Alt+F4
Unmaximize window: Alt+F5
Move window: Alt+F7
Resize window: Alt+F8
Minimize window: Alt+F9
Maximize window: Alt+F10
Activate window menu: Alt+Space
Shift+Ctrl+Alt+Arrow: Move window to another workspace

Firefox
Close tab: Ctrl+F4
New tab: Ctrl+T
Switch tab: Alt+1..8 or Ctrl+Tab
Switch to last tab: Alt+9

X-Chat
Switch channel: Alt+1..9 or Ctrl+Tab