I would like something that is simple to use.
Menubar Countdown is good if you just want to countdown something http://capablehands.net/menubarcountdown
License Menubar Countdown is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
It's not a dashboard widget, but the Apimac Timer application is free (there's a paid Pro version with additional features) and functions as a stopwatch, countdown timer, and alarm clock. Nice and handy.
For counting down a repeating task, Pomodoro is useful (and free): http://pomodoro.ugolandini.com/
Not a widget, but since there's always a browser around, the Timer Tab web app does the trick for me.
Here's a selection of features:
- timer + alarm clock + stopwatch
- works offline
- fullscreen countdown by clicking on the countdown
- keyboard control:
- →, ←, ↑, ↓: control inputs,
- f: toggle fullscreen,
- space: toggle pause
- audio alarm: any Youtube clip
- background: any image on the web
- countdown in the browser tab title and tab icon
Now, if Chrome happens to be the browser of your choice, there's also the Chrome app, providing you with some extra features:
- optional sound and Chrome notification
- use the "tab to search" chrome feature to set the timer
Now, it's up to you to consider if this is a reasonable alternative to a widget.