Keyboard Shortcuts

Ctrl+E = Send To... (Send the current document to an email recipient or remote location, not in terminal)
Ctrl+W = Close (Close the current document, not in terminal)
Ctrl+Q = Quit (Quit the application, not in terminal)

Ctrl + Alt + F1 = Switch to the first virtual terminal
Ctrl + Alt + F2(F3)(F4)(F5)(F6) = Select the different virtual terminals
Ctrl + Alt + F7 = Switch to current terminal session with X

Ctrl+Alt++ = Switch to next X resolution (Depends of your X configuration)
Ctrl+Alt+- = Switch to previous X resolution (Depends of your X configuration)

Ctrl + Alt + Backspace = Kill X server

Alt + Ctrl + L = Locks the screen.
Alt + F1 = opens the Applications menu, then use the arrow keys to navigate the submenus.
Alt + F2 = opens the Run Application dialog box.
Alt + F3 = opens the Deskbar Applet (F3 opens the search bar at the bottom of the window).
Alt + F4 = closes the current window.
Alt + F5 = unmaximizes the current window (if it's maximized, of course).
Alt + F7 = , followed by arrow keys or mouse movement, adjusts the current window's position.
Alt + F8 = resizes the current window.
Alt + F9 = minimizes the current window.
Alt + F10 = maximizes the current window.
Ctrl + Alt + Tab = moves between open panels on the desktop.
Ctrl + Alt + D = Show the desktop
Ctrl + Alt + Backspace = Restart session and recover from crashes
Ctrl + Alt + Delete = Restart the computer immediately, without saving open files

Command line / Terminal shortcuts

Ctrl+C = Kill process (Kill the current process in terminal, also used to copy elsewhere)
Ctrl+Z = Send process to background
Ctrl+D = Log out from the current terminal. In X, this may log you out after a shuting down the emulator.

Ctrl+A = Home (Move cursor to beginning of line)
Ctrl+E = End (Move cursor to end of line)
Tab = List available commands from typed letters (Ex: type iw and click tab, output = iwconfig iwevent iwgetid iwlist iwpriv iwspy)

Ctrl+U = Delete current line
Ctrl+K = Delete current line from cursor
Ctrl+W = Delete word before cursor in terminal (Terminal only, also used to close the current document elsewhere)

Arrows up and down = Browse command history
Ctrl+R = History search (Finds the last command matching the letters you type)

Shift+PageUp / PageDown = Scroll terminal output
Ctrl+L = Clears terminal output
Shift+insert = Paste

Alt + F = moves forward one word.
Alt + B = moves backward one word.


Nautilus / Gnome

Ctrl + H = show hidden files
Ctrl + T = move to trash
F9 = toggle side-pane
Alt + Home = jump to home folder
Alt + Enter = file / folder properties
Alt + F1 = launch applications menu
Alt + F2 = launch "run application" dialogue


Firefox

Ctrl + K = firefox search field
Ctrl + L = firefox address bar
Ctrl + PgUp = next tab (Left to Right)
Ctrl + PgDn = previous tab (Right to Left)
Ctrl + T = new tab
Ctrl + R / F5= reload page
Ctrl + U = view page source