Nivo Slider is the best jQuery image slider I have ever seen. Nivo Slider is not an old fashioned robot but it moves like a natural water. It is free to use under the GPL license.

* 9 unique transition effects
* Simple clean & valid markup
* Loads of settings to tweak
* Built in directional and control navigation
* Packed version only weighs 5kb
* Free to use and abuse under the GPL license