Resize a window automatically to an exact predefined size, with Sizer
Sizer is a small and free utility that will let you resize any window to an exact predefined size. This can be especially useful when designing web pages.
It can be also very handy when one compiles screenshots for documentation. Using Sizer allows you to easily maintain the same window size across screen grabs.
Sizer would also be part of your strategy for designing a workspace on your desktop.
Combine Sizer with Window Manipulator, a freeware that lets you drag a window from anywhere and not only its title bar or corner to move or resize it, even bring it to the center of the screen instantly and restore it to its original position at a click of your mouse.