I know there have been a zillion and a half posts written about the best plugins for WordPress, but I thought I would throw my hat in the ring and offer up my favorites. Some are the common ones that you'll find on many other lists, but some are ones that I've had to dig for to fulfill a unique need that I had. If you're a WordPress veteran, maybe you'll find a gem in this list that you apply to your site. If you're new to WordPress, you'll likely find many of the plugins on this list that you'll want to add to your site.
If you're annoyed by the fancy quotes that WordPress replaces your normal quotes with (i.e. “these quotes” rather than "these regular quotes"), there's an easy way to get rid of them. Just use Semiologic's Unfancy Quote Plugin For WordPress and presto chango, your fancy quotes are gone!
I know there are a lot of widgets and plugins for WordPress out there for adding a Digg badge to posts (I know, because I tried half a dozen or so of them) but I didn't find any that worked consistently and provided the functionality I wanted. After researching the Digg Tools API and a few other examples online, I've composed this block of code for generating Digg badges.