BetterSnapTool (OS X)

I thought I'd point people out to this application that I found about a month ago that gives you the snap to window functionality that was introduced in Windows 7 in OS X.  Since I moved to a Mac Book Pro 15' as my primary work device with multiple monitors I really struggled with the ability to move windows across multiple screens and constantly having to resize windows to fit.  I found BetterSnapTool on the app store and and for a small cost of £1.49 it's possibly been the best purchase I've made.

There are a wealth of options available to configure how the application works with regards to snapping to specific area's of the screen as well as right clicking on the close, minimise or maximise window buttons:

The below screen shot shows you a notepad application being dragged into the top left hand side of the screen and the application being automatically resized to fit accordingly:

If you miss the snap to windows functionality from Windows 7 then I advise you to check the application out, especially if you use multiple monitors.