Using Chrome's Element Inspector in Print Preview Mode?

Note: This answer covers several versions of Chrome, scroll to see v52, v48, v46, v43 and v42 each with their updated changes.

Chrome v52+:

• Open the Developer Tools (Windows: F12 or Ctrl+Shift+I, Mac: Cmd+Opt+I)
• Click the Customize and control DevTools hamburger menu button and choose More tools > Rendering settings (or Rendering in newer versions).
• Check the Emulate print media checkbox at the Rendering tab and select the Print media type.

Chrome v48+ (Thanks Alex for noticing):

• Open the Developer Tools (CTRLSHIFTI or F12)
• Click the Toggle device mode button in the left top corner (CTRLSHIFTM).
• Make sure the console is shown by clicking Show console in menu at (1) (ESC key toggles the console if Developer Toolbar has focus).
• Check Emulate print media at the rendering tab which can be opened by selecting Rendering in menu at (2).

Chrome v46+:

• Open the Developer Tools (CTRLSHIFTI or F12)
• Click the Toggle device mode button in the left top corner (1).
• Make sure the console is shown by clicking the menu button (2) > Show console (3) or pressing the ESC key to toggle the console (only works when Developer Toolbar has the focus).
• Open the Emulation (4) > Media (5) tabs, check CSS media and select print (3).

Chrome v43+:

• The drawer icon at step 2 has changed.

Chrome v42:

• Open the Developer Tools (CTRLSHIFTI or F12)
• Click the Toggle device mode button in the left top corner (1).
• Make sure the drawer is shown by clicking the Show drawer button (2) or pressing the ESC key to toggle the drawer.
• Under Emulation > Media check CSS media and select print (3).

Changed in Chrome 32 35+

(In Chrome 35+ the "Emulation" tab is present by default. Also, the console is available from any primary tab.)

1. In DevTools, go to settings-> Overrides
2. enable "Show Emulation view in console drawer"
3. Close settings, go to 'Elements' tab
4. Hit Esc to bring up console
5. Choose tab "Emulation", click "Screen"
6. Scroll down to "CSS Media", select "print"

This option is not (yet?) available in the console tab.

Since Chrome 32 you have the CSS media option in the Screen section of the drawer Emulation tab.

Just enable it, select print as the target media type, and - behold - your page is rendered [almost] the way it will be printed.

Use Esc to bring up the drawer if it's not visible.