Alt+Tab Replacement - TaskSwitchXP
In my "spare time" I like to tweak windows and recently I've started using alternatives to the standard Alt+Tab behaviour provided by Windows XP.
A quick search on Google for alt-tab replacements returns more results than there are candles on your grandmothers birthday cake.
The one I've settled on is TaskSwitchXP. Why? Because it not only provides a better alt+tab experience, but you get a few things that most others don't provide such as process information (see the image), it works with non-standard themes (like the Zune theme), supports multiple monitors and it's quick.
There are of course other tools you can use, in case you don't like this one. For instance you have
If you've got a personal preference, leave me a comment ;-)