Create Tables inside post/page : WP-Table Reloaded
Scroll to top plugin will add a button that hovers in the bottom right corner of your screen that allow users to smoothly scroll up your page : Scroll to Top Plugin
Search Engine Optimization : All in One SEO Pack
Photo Gallery : NextGEN Gallery
Animated Banners : Featured Content Gallery
Online Form Create : Contact Form 7, cforms II
Ecommerce : WP e-Commerce
Security & Privacy : Login LockDown, WP Security Scan
Cache : W3 Total Cache
Backup Database : WP-DB-Backup
Share, Bookmarks & Subscribe : Sociable, Add to Any
Discussion Forum : bbPress Forum
Events Calendar :
Google Maps : Google Maps Anywhere
Custom Field : Custom Field Templates
Custom Field Search : WP Custom Fields Search
Hide Dashboard : WP Hide Dashboard [dashboard cleanup]
Post Page redirect : Redirection
PHP code in widget : WP PHP widget
Spam Protection : Math Comment Spam Protection
Magic Field : http://wordpress.org/extend/plugins/magic-fields/
Video Plugins:
http://elearningtech.blogspot.com/2007/10/video-format-comparison-flash-wmv.html
http://www.themelab.com/2008/05/03/easily-add-videos-to-your-wordpress-blogs/
http://www.reelseo.com/top-wordpress-video-plugins/