In addition, you can dig into the paid side of search and find out what keywords your competitors are bidding on, and then leverage those keywords for your own organic benefit if you're not already doing so. Search Metrics does this as well, but I've found SEMRush to provide a greater range of keywords and they save more historical keyword data than Search Metrics.
It’s very easy to use, fast and smooth and gives you tons of Long Tail Keywords. You only pay for the web based software once, so there are never any monthly fees. I’ve also been impressed over the years at how easy it is to update. These updates are free and the creator (Clever Gizmos) is always moving with the ever changing world of SEO and updated API’s to keep his program up to speed and fresh.