jQuery is great for doing validation on the fly, but the standard filters do not cover everything like Australian phone numbers for example.

The 'JJ NextGen JQuery Cycle' allows you to create a 'Cycle Lite' (http://jquery.malsup.com/cycle/lite/) as a widget or as a shortcode. This plugin uses the 'NextGen Gallery' plugin for its images.

JJ NextGen JQuery Slider is an excellent way of presenting images on your WordPress site. It uses the Nivo slider.

Add a neat star rating symbol to your articles. This example does not allow the user to change the rating.