ClocX - ClocX - freeware analog clock for Windows desktop with many features like calendar, alarms, skins, antialiasing and transparency.
Gnome Clocks - Clock application designed for GNOME 3
LClock - Longhorn systray clock program
Digital Clock 4 - Beautiful customizable clock with plugins
DS Clock - Keep your time synchronized with Atomic Time servers, using customizable digital desktop clock with westminster chimes.
AlarmDJ - Online Alarm Clock - Use YouTube videos or MP3 files as alarm sound. Works offline.