Mac: There a few tools out there that simplify windows management on Mac, but Gridsutra's one of the easier ones to use because it lets you organise with keyboard shortcuts or a few clicks of the mouse.
Tagged With window management
Windows: Preme adds a collection of useful tweaks to window management on Windows, including the ability to scroll windows without clicking on them. We featured Preme once before, but it bears repeating now that Windows 8 is out and this app has been updated with a nicer interface.
Gmail's new Compose window docks the small message window in the bottom right corner of your inbox. If you'd rather move the window elsewhere or resize it for more space, you could click the popout arrow in the window, or, better yet, use this shortcut to quickly open the message window centred on your screen.
Windows: Sometimes you have more windows on your screen than you can deal with at once, even when you're using a good window manager. Peek Through makes any window temporarily transparent with a hotkey, then lets you click through to the window below it.
Windows: Dexpot is an awesome tool that brings virtual desktops -- similar to Mac OS X's Spaces -- to Windows. It has just updated with a host of new features including full screen previews, lots of smoothness and multi-monitor support.
Mac: Divvy, the awesome app that splits up and organises your windows for maximum productivity, is 50 per cent off in the Mac App Store right now at only $7.49.
Mac: One of the benefits of being a cross-platform kind of person is that you get to use the best features of multiple operating systems in your workflow. Unfortunately, the ability to snap windows to the side of the screen and shake to minimise aren't available in Mac OS, but iSnap is a utility that duplicates them on the Mac nicely.