The plugins you use will really depend on what you want the site to do. Wordpress plugins add functionality to a site.

All in One SEO is a good one to start with as it covers basic site SEO.
Google Sitemap Generator should also be included.
WP DB Backup is vital for easy backups.

The rest will depend on your needs and wants for your own site.

Here are my favourites:

Basic Set:
akismet
all-in-one-seo-pack
google-analyticator
google-sitemap-generator
wordpress-automatic-upgrade
wp-db-backup
enhanced-wordpress-contactform

If you need to redirect pages:
redirection
wp-affiliate

Check out your site security with this plugin,
WP gets hacked a lot:
wp-security-scan

Other useful plugins:
wp-sticky - keep selected posts on top
podpress - great for audio/video podcasts

In addition the ones listed:

Embed It
Simple Tags
Sociable
WP Traffic

One useful plugin that I really like is "What Would Seth Godin Do".

You can read about it here:
WordPress › What Would Seth Godin Do WordPress Plugins

Thank you for your post freedomguy, I'm just starting setting up my wordpress blog and these will help me get started for sure! Many thanks!

really NOT that many.

Google XML sitemaps.
Platinum SEO

( Not mentioning already included or "special" plugins like WP Autoblog plugins )

I also think "tinymce advanced" is nice, depending on your needs.

A few more that can be useful -

Post teaser: This is a plugin that shortens posts on the main page and adds a read more link to the actual post. Helps avoid duplicate content.

Duplicate content cure: The name says it all! Only works on pages within a single blog of course, not with content on external sites.

Old Post Promoter: I just just grabbed this one recently and it's brilliant for PLR filled blogs. Lets say you have a blog filled with 50 PLR articles, it will randomly place old posts back at the top of the blog. Providing the permalinks just show the post name, there there won't be any duplicate content issues with this one either.

There's a bunch of others, I just can't think of them right now.

Here is one I just started using on one of my blgos: Sociable
it allows your readers to submit your post to many of the Social Networking sites like Digg, StumbleUpon, Reddit, etc.

A couple more for your list: SEO master, excellent plugin with a really easy way of controlling page rank flow through your site. Also, Theme Tester which as its name suggests, allows you to test out new themes on you site without affecting your live site

Hey Warriors,

I think Lorelle has covered a comprehensive list over here: Lists of Your Favorite WordPress Plugins Lorelle on WordPress

Just check it out in case there's any wordpress plugins you'd find it useful for your WP blogs.


Cheers,
Dominic

With my blog I've found that the sociable plugin very useful as it lets your visitor bloggers to send your blog posts to all of the popular social bookmarking sites starting with Digg and Propeller and Stumbleupon. It allows quick indexing of your blog via wordpress, which in turn generates more traffic to your blog! A great tool!

XML Sitemap Generator and WP-Supercache (if you have high traffic) is essential, rest isn't as important in my opinion.

I would add wp-autotagger and hyper cache over super cache, but just a matter of preference. Also prefer Platinum SEO over All in One.

This useful information is timely. I just need somebody there to tell me how to install all these plug-ins.

This useful information is timely. I just need somebody there to tell me how to install all these plug-ins.