The Best, Free WordPress 3.1 Plugins
There are thousands of WordPress Plugins out there, but it takes a lot of time and trial to find the ones that are truly exceptional. After years of building custom websites, I’ve decided to refine and publish my master list of plugins (for the user, not the dev) that are awesome or essential to nearly every site I have launched!
Galleries
WordPress is getting more robust with every release, yet for some reason, there’s still no great way to do Galleries natively. Fear not, we have found that Nextgen and CataBlog will do the job well enough!
Worpress and Search Engine Optimization
When it comes to SEO, there are absolutely no open source platforms that I’ve seen that do as superb of a job providing tools and automating the process. Keys to wordpress SEO include meta control, monitoring, links and social networking. Here are the best tools for the job:
WordPress Stats Plugin
The WP Stats is actually two essential plugins, one by the creators of WP and the other as a dashboard tool to take analytics through the roof. The WP stats plugin lets you monitor social traffic, alexa, compete, and far more — all enabled and monitored without leaving your admin!
WordPress SEO by Yoast
For years, i used the All in one SEO plugin, and even gave headspace a shot but Yoast knocked them both out of the water for me. The yoast plugin boasts some great tools to help you generate meta content, plus looks and works the way a good WP plugin should.
SEO Smart Links
Internal site links are a huge usability and SEO boost, and nothing helps you build these links better than this plugin. I usually dump in a keyword list that I’ve built with Google’s Keyword tool and over time I aim to write articles and link them to those keywords.
Worpress SEO requires a Sitemap
Don’t let the name fool you, Google SEO sitemap covers all the major search engines and notifies them automatically whenever you publish new content. Don’t skip this one, a sitemap is a must in helping a search engine index your site, and is even more crucial for frequent bloggers.
Faster page loads in WordPress
We all want more cache don’t we? WP Super Cache speeds up your site significantly making your pages load faster, which is favorable for both man and machine! Follow that with Smush.it, Database Optimization and Minification and you’re looking at a 20-30% faster site on average (estimated from personal use and client sites).
Get Social with WordPress
Social networking is huge and most blogs completely fail to engage their audience (guilty), part of the problem is obviously content but the other part is often the tools and approach. If your website is large and well known (or has the capacity to be) why not extend WordPress with BuddyPress and launch your own social network? Or keep it simple and drop in Socialize widgets and Disqus Comments so that your users can engage using existing social platforms.
WordPress Utilities you can’t Live Without
There are a TON of utilities that I would love to talk about, but for brevity I will only mention Scissors and WP DB Backup. Scissors lets you crop and rotate media which is something I hope wordpress will include in its core. WP Backup makes a data backup for you automatically and emails it to you, allowing you to have a backup outside of your host.
I hope these plugins help, and if you feel I missed one that HAS to be on the list, just mention it in the comments below and I’ll argue about it a bit 
