Keypirinha - A lightning fast and flexible keystroke launcher for Windows. No installation required (portable).
RocketDock - RocketDock is a Mac OS X dock clone.
Listary - Listary is a revolutionary search utility for Windows
Docky - . applications and managing windows easier and quicker. Docky is fully integrated into the GNOME Desktop and features a no non-sense approach to configuration and usage.
Alfred - Your To-Do List. Done.
ObjectDock - ObjectDock is the most popular animated dock for Windows.