I am probably the ten billionth person who says this, but jQuery this just GREAT! By spending a few extra minutes you can add so much interaction to your website. It is so easy to understand and use, you do not even need to be able to create your own. So many plugins out there that can make life so much easier. Here are five plugins that are not only nice, but also easy to implement:
FancyBox is a tool for displaying images, html content and multi-media in a Mac-style “lightbox” that floats overtop of web page.

This plugin is a jQuery styling plugin wich allows you to skin form elements.

Supersized resizes images to fill browser while maintaining image dimension ratio, cycles Images/backgrounds via slideshow with transitions and preloading.

The purpose of this library is to make it extremely easy to add scrolling functionality to a website. Whenever you wish to scroll HTML elements in a visually-appealing manner, this is the only library you need. The main design goals of this library are to provide visual customization functionality and programmability.

TipTip is a very lightweight and intelligent custom tooltip jQuery plugin. It uses ZERO images and is completely customizable via CSS. It’s also only 3.5kb minified!

Kudos for the programmers who developed these great plugins!