Here is a list of must have plugins for self-hosted Wordpress blogs…

Search Engine Optimization:

• Google Analyticator - Google Analyticator adds the necessary JavaScript code to enable Google Analytics logging on any WordPress blog. This eliminates the need to edit your template code to begin logging.
• Google XML Sitemaps - This plugin will create a Google sitemaps compliant XML-Sitemap of your WordPress blog.
• All in One SEO Pack - Optimizes your Wordpress blog for Search Engines by adding the necessary meta tags to all of your posts.
• Feedburner Feedsmith - The plugin will detect all ways to access your feed and redirect them to your FeedBurner feed so you can track every possible subscriber.

Photo Gallery

• NextGEN Gallery - I don’t care what anyone says, this is the VERY best plugin for turning your blog into a photoblog, displaying multiple galleries on one page, whatever you need to do, there are endless possibilities with this plugin!
• FlickrRSS - If you just want to add a few photos to from your flickr gallery this plugin is super simple to use. Just insert a small amount of code to display your feed in a post or on a page.

Random Plugins

• Wordpress Related Posts Plugin - WordPress Related Posts Plugin will generate a related posts via WordPress tags, and add the related posts to feed.
• Breadcrumb NavXT - This plugin generates breadcrumb navigation bars for your WordPress blog.
• Contact Coldform - A simple, easy to use and customize contact-form plugin for WordPress.
• Separate Comments & Pings Plugin - This plugin quite simply separates your comments and your pings!

“May not need but probably want” Plugins

• Last.fm Records Plugin - This plugin shows cd covers on your Wordpress weblog. It connects to last.fm and grabs the list of cds you listened to recently and tries to find the cover images at last.fm.
• Simplelife - Simplelife takes your feeds from around the internet and aggregates them into one online trail.
• Favicon Manager - This is a small plugin that allows you to manage the favicon image for your WordPress installation.
• Twitter Tools - Twitter Tools is a plugin that creates a complete integration between your WordPress blog and your Twitter account.