Nobody seems to be talking about windows management on OS X. You hear about Hazel and TextExpander, but never about how to easily move windows around. If you're a developer or a writer using multiple apps at the same time, it's easier now to have apps side-by-side on iOS than on OS X.
In comes a little app called Divvy by Mizage. Divvy makes the process of moving and resizing windows a breeze. Instead of dragging and resizing windows with the cursor, Divvy works by dividing the screen into a rectangular grid. You then invoke the Divvy interface and either draw directly on the grid to move a window or you can setup hotkeys for specific regions that you use often. For example, I have setup a 2x2 grid and have keys to move windows to the left, right, top, and bottom halves of the screen. You can also invoke Divvy and draw on the grid if you need a more specific region of the screen.
When I'm doing research in Safari while writing in Byword, or previewing a markdown file, I can have the windows side-by-side with just two hotkeys.
You can customize the granularity of the Divvy grid and assign as many keys to as many regions as you want. If you have a larger, high-resolution monitor you might want to setup a 3x3 grid for a maximum of 9 perfectly aligned applications at one time.
Divvy has become a vital part of my daily work. You can buy Divvy on the Mac App Store for $13.99 or check-out the trial version. A great little application that makes your Mac easier to use every day.