MS is a great tool. I have it myself. It is expensive though so if you are a little short on cash, I feel Google's keyword tool works well.
What other keyword tools do you recommend for a newbie that are easy to use and understand? I, like many others I presume, are not looking to dominate search engines, but we would like to focus on keywords that give us a good advantage over simply wingin' it.
Google is my personal favorite. I know a lot of people like Wordtracker too which can be found here: http://freekeywords.wordtracker.com/