Best Chat Plugin: Envolve Chat
Envolve chat is a customizable chat toolbar for your website.
Best Cache Plugin: W3 Total Cache
Improve site performance and user experience via caching: browser, page, object, database, minify and content delivery network support.
Best Plugin To Syndicate Feeds to Post: FeedWordPress
FeedWordPress is an Atom/RSS aggregator for WordPress. It syndicates content from feeds that you choose into your WordPress weblog; the content it syndicates appears as a series of special posts in your WordPress posts database.
Best Sharing Plugin: Shareholic
Adds an attractive social bookmarking menu and related content widget to your posts, pages, index, or any combination of the three.
Best Page Navigation Plugin: WP-PageNavi
Replaces Older Posts & Newer Posts with more advanced paging navigation interface of page numbers.