If you are looking at an analytics suite, I would identify all of the items you want to track and be able to do within a platform. I would start with Google Analytics, as that is a free software. If you have basic metrics, try Google Analytics and then maybe adding a third party app like Crazy Egg for a heatmap on your site. Some companies don't need all of the bells and whistles that Omniture or Webrends can give. So be sure to identify your needs.