I got myself for Christmas....
This tiny little stinker is essential for calibrating my screens. I have no idea if you ever had the chance to calibrate *your* screens but having a good screen also means you might want to invest in a buddy who helps you to see the actually correct colors. Nobody wants to be shocked in the final print version. Though I have to admit: If the printer messes up you'll end up shocked anyway. But it's a good start and for me essential.
IF you think "Oh shiny... me wants" check the Datacolor hardware. There are different versions of the Spyder. I had a OneEye before which was fine as well.