WinSplit Revolution makes the task of shuttling and resizing windows around your desktop quick and automatic. By default it assigns a hotkey for nine different window placements.
The number pad layout corresponds to WinSplit's hotkey positions, such that hitting Ctrl-Alt-1 moves and resizes a window into the lower left corner of your desktop, Ctrl-Alt-4 puts it along the left side, Ctrl-Alt-5 goes in the middle, etc. You can cycle through two or three different windows sizes for any given position by hitting the same hotkey again, and you can also go into the tool's settings to define your own window positions and sizes.
For handling multiple windows, WinSplit can automatically tile your open windows in a mosaic, or create a 'fusion' display for comparing two windows side-by-side. Still more features in an 'Active window tools' menu allow for setting any window as transparent or always on top, or taking a screenshot.
The handy little tool runs out of the system tray, and can be set to launch with Windows. It's best suited for larger monitors--or multiple monitors--that can comfortably display several windows at the same time.