Here are the first few plugins you need after installing Wordpress:

  1. Akismet: Plugin to stop comment spam. As a small example of the problem of spam, I run a very very small blog. Last week, I trackbacked two posts and commented two times on other small blogs. This led to receiving about a hundred comment spam last monday!

  2. Ultimate Google Analytics: Plugin that integrates Google Analytics on your website. GA gives you traffic stats. You do want to know if your blog is read, do you?

  3. Feedburner Feedsmith: Feedburner is a service you need for your blog. First, it allows to transfer all your feed traffic to them (this can represent a fairly large amount of your bandwidth in terms of percentage) and it gives you stats on who subscribes to your feed.

These 3 plugins are a good start to take control of your blog.