Windows 7 certainly brought this very useful feature of maximizing an app window from the keyboard. You can also get app windows to use half the screen (left or right) with your keyboard only.
I have added an app to my Mac to do the same and now I have configured KDE tohave the same convenience:
System Settings => Shortcuts and Gestures => Global Keyboard Shortcuts and choose KWin from the KDE component dropdown.
You are looking for the Quick Tile and the Maximize Window actions.
Cinq 