Power
[codesyntax lang="bash"]

Lock screen: ctrl + shift + eject
Sleep: command + control + eject

[/codesyntax]

Screen
[codesyntax lang="bash"]

Screen capture (whole screen): command + shift + 3
Screen capture (selection): command +  shift + 4
Screen capture to clipboard (whole screen): command + control + shift + 3
Screen capture to clipboard (selection): command +  control+ shift + 4

[/codesyntax]

Finder
[codesyntax lang="bash"]

 Get info: command + control + i

[/codesyntax]