LongTailPro - It is a great keyword search tool. It provides score keyword Competitiveness.
With this tool, you can easily manage the profitability of Keywords, rank and filter them by CPS, keyword competitiveness and local searches. LongTailPro is suitable for Adsense Site as well as Amazon site. Just add your domain to a project and you could determinate the keyword difficulty for each of your sites! LongtailPro provides Affbank Members - 30 % off the price!