When it comes to window-management, Mac OS X wins hands-down. Exposé and Spaces are a great way to manage open windows and applications within your desktop environment. However, I'll have to admit that there is one Windows 7 feature wish I had on my Mac: AeroSnap. Being able to drag a window to the top of the screen to have it maximized, or to the left or right of a screen to create a split-view is awesome. There was no easy Mac solution to incorporate this amazing UI feature, that is, until now.
Cinch, by Irradiated Software, provides an implementation of AeroSnap just for Mac. Similar to its Windows counterpart, Cinch allows you to drag any standard Mac OS X window to the top, left, or right edge of any screen and allows you to maximize or fill half of that screen. Cinch also has multiple-display support, unlike Windows 7 that does not honor the midpoints between screen layouts (at least in my testing).
I have greatly enjoyed using Cinch: the convenience of easy window resizing is easy to grow accustom to, especially when it is executed so well. This feature comes in handy quite often, especially when you need to manage or compare files between two folders, or if you want to open two webpages to compare information.
I hope that in the near future Apple decides to include this feature natively into Mac OS X (one of my feature requests for 10.7). For once Apple, please copy Microsoft; this is a feature that every Mac OS X user should have.
Until Apple decides to implement a feature similar to AeroSnap, Cinch totally fits the bill and is worth every dollar.
For more information about Cinch, you can visit the Cinch homepage. Cinch is $7, but a trial is available.