Here is my list of plugins I have installed on at least one of my 3 main websites:
AddThis Social Bookmarking Widget – probably one I will get rid of in favor of the “Tell-a-Friend Widget Plugin”.
Akismet – a must have for killing spam.
All in One SEO Pack – of course.
Cimy User Extra Fields – Used to allow revenue sharing between authors.
Contact Form 7 – Nice and easy to use contact form.
FD Feedburner Plugin – Before writing this I didn’t realize I have different Feedburner plugins on different sites.
Feedburner Feed Replacement – for all your RSS goodness.
FeedBurner FeedSmith – Wow, actually 3 different feedburner plugins.
Google XML Sitemaps – Google Love!
Photo Dropper – rarely ever used – maybe I’ll try to use it right here.
RSS Footer – nice to add links back to article inside RSS feeds.
SABRE – This one I’m not sure how well it is doing. If it works I should not have to know it is even there.
Simple Tags – This is a great one and I need to start using it on all sites.
Tell-a-Friend Widget Plugin – Currently my favorite “Social Media Sharing” plugin/button.
Twitme – Must have to automatically announce new posts on Twitter.
Yet Another Related Posts Plugin – Shows links to related posts at the bottom of each post.
What important plugins am I missing?