Here is a compilation of WordPress plugins that I currently use and am satisfied with. I know there are others that do the same thing, so feel free to leave comments and let others know what you are using.
Do-Follow – Disables “no-following” of links. Highly recommended for all bloggers.
Spam Karma – Blocks Spam – Somehow, I do think spam elicits bad karma – as it should.
All in One SEO – Allows for Optimization of Posts for Search Engines. Assuming that a high percentage of bloggers do so for online exposure, this is a must.
Google Analytics – Allows for tracking with Google Analytics. How will you ever sell ads on your blog if you don’t know how many people visit?
Subscribe To Comments – Allows users to subscribe to posts they comment on which helps to increase your return visitors and build community at your blog.
WP DB Backup – Simplifies the process of backing up your blog, which you should do periodically.
Sociable – Simplifies interaction with Social Media websites.
Google AdSense – Allows for monetization of your blog with Google AdSense. Use with caution lest you send your visitors away for pennies.
Hope those are helpful. Let me know if you have any questions about any of them and feel free to subscribe to my blog to get more free online business development tips.