Once I have a list of phrases, rankings, and volumes from these tools, I'll look to internal tools (maybe Excel, Access, or another database) to organize, classify, and forecast opportunity. This is where I'll estimate a competitor's traffic based on volume & position CTR, set goals for a target position, and estimate traffic based off that position's CTR and keyword volume.
Answer: Google Keyword Planner was created to find keywords for Google ads. It will likely not produce very good keyword suggestions for SEO or content marketing purposes. Google Keyword Planner often hides good long tail keywords. To find long tail keywords for SEO, you can use Keyword Planner alternatives such as Google Trends, Google Suggest or Keyword Tool.
But it’s still very useful for getting search volume data (provided your account still shows this), which is helpful when choosing which of the many keywords you’ve found to focus on (although you should take these estimates with a pinch of salt, they are still useful in indicating the relative search volumes of different keywords, even if the absolute estimates are a little off).
This keyword research tool is effective, automatically providing you with keyword suggestions that other sites haven’t necessarily turned up (which it’s intended to do), along with their search volume, CPC, and Adwords competition. In order to get any actual information about the keywords, though, you need to upgrade to Keyword Tool Pro (which is a little misleading on the site copy). This plan is $88 a month, and if you’re just doing keyword research for Google, I’d recommend choosing one of the other tools for the price.
Spencer, it seems like you got out at just the right time and made your money? Seeing as Google has basically stopped giving access to their free keyword tool. I own the FULL lifetime license $290+ I think is was. Now Longtail Pro is useless due to the restrictions that Google has put in place. Do you know what the future plans are for Longtail Pro to get around this issue that I’m sure everyone is facing? Or can you get some feedback from the new owners?

In a nutshell, Long Tail Pro helps you quickly find keywords in bulk based on a seed keyword that you input.  In addition to returning hundreds of related keywords, the tool also shows search volume (monthly search volume), advertiser bid, number of words, rank value, and my favorite Keyword Competitiveness (helps you judge the competition and keyword difficulty).