I have sorely missed the simple keyboard shortcut from Microsoft Windows to maximize a window (alt+space x).
There are many other solutions out there for a Mac based on AppleScript & a 3rd party application to invoke it using a shortcut (like Quicksilver). But there is a way to do this for most applications without installing any other applications.
Almost every application has a "Zoom" menu-item in the "Window" menu which does the same action as clicking on the Maximize button on the left corner of the window.
So, here are the steps to setup a keyboard shortcut for this:
1. Open System Preferences
2. Go to "Keyboard & Mouse"
3. Navigate to the "Keyboard Shortcuts" tab
4. Click on the "+" button below the list
5. Set the "Application" drop down to "All Applications"
6. Set the "Menu Title" to "Zoom" (no spaces)
7. Set any keyboard shortcut. I have set Cmd+Shift+M (opposite of Cmd+M which is the standard shortcut for minimize)
8. Click on Add
9. In the "Keyboard Shortcuts" tab, scroll down to see "Application Keyboard Shortcuts" at the end. Expand it to see "All Applications". Expand this to see the new shortcut you just created.
10. Close System Preferences
You are done. Now go to any application, press your shortcut & enjoy a maximized view of the application.