WinShake

Note: This review addresses v2.51 of the software.

Win 7's Aero Peek feature turns windows transparent, giving you X-ray vision for determining what lies beneath. Its Aero Shake function lets you minimize every window but the active one via a simple shortcut. The free WinShake app brings similar capabilities—and then some—to most of Win 7's precursors.

--Adam Pash