I also hang out in SEO forums and groups and see KC scores tossed around and talked about and pretty much everybody is on the same page. Most agree that you can’t completely rely on the KC score (there are a few factors that can’t quantitatively be measured with a number) – but that the KC score is a VERY good indicator of the competition level for specific keywords. The following diagram realistically shows exactly what to expect from certain KC scores…

4. Set post-search filters. After your keyword suggestion fetch is completed — which might take a while if you input a lot of seed keywords — you need to filter your list. You can: filter out keywords that don’t include buyer modifiers like “best”, “buy”, “purchase”, “discount”, “review” (it’s possible to input one or more words in the filter field at the same time: just separate the words with a comma); add a minimum and maximum amount of LMS; set a minimum amount in “Suggested Bid”; and check for only high “Advertiser Competition” keywords.
You can receive keyword ideas from your audience or team because people are a rich source of keyword date. Seed keywords presents a unique tool that users utilize in generating keyword ideas from other individuals. You need to begin by creating a scenario in a question form by asking people what they would search for in case they are looking for answers to their questions. Seed keywords will develop a unique URL that you can share with your relevant audience or team once you have created a scenario. Your viewers will begin to enter their desired keyword phrases and this will be added to the seed keywords. This data is downloadable in the form of a CSV or you can simply click to view the results of each keyword in Google. You can look for the search volumes in other keyword tools like Google planner once you have your list of keywords.
Keyword Researcher is designed to search the Autocomplete databases of Google, YouTube, and even Amazon.com. That's a lot of keyword sources! As you probably know, if you're building an authority site, or if you would like to become a dominant player in your niche, then starting with a large database of keywords (that your customers are actually typing in) is a powerful marketing tool.
The reason I sometimes use this facility with the GKP is to find volume amounts for the keywords I’ve chosen. But, these days, it’s not so important. As long as the Long Tail Keyword makes sense and is something I would put into a search engine, then it’s good enough. Sometimes the most blazingly obvious keywords are often over looked by eager, trying-to-be-clever marketers. Sometimes you need a tool to highlight them.
You can try DeepMiner. It is good for scrapping, rank position, generating long tails and keyword suggestions. You can export the data to document for later analytics. You can find popular keywords that people are searching for. 7 major engines are supported, Google, Yahoo, AOL, Amazon, YouTube, Ask, Bing. It supports multi-threading so it is very very fast scrapper. BTW you must use proxy list if you plan to scrap thousands and thousands of keywords.

Using the good ol' free Google Keyword Planner is great. But there is an alternate universe of Long Tail keyword phrases that live in Google's other database--namely, their "Autocomplete database." That's the database that is accessed when you're typing queries into the Google search box (notice that list of suggested keywords that pop up as you type?)
So whilst Long Tail Pro has just continued to grow in revenue every single year and comes highly recommended, you may want to check if all the important features are fully functioning before signing up. Especially the KC feature (keyword competitiveness) as it is so fundamental to keyword research and making an informed choice on whether or not to go into a particular niche.
The limit on manual keywords could be higher.  I personally wish we could input 10,000 keywords at a time, instead of 200.  However, I understand the costs that Long Tail Pro has to maintain each time a new manual keyword is input.  Not a deal breaker, I just wish the limit was higher. (To be fair, I don't think most keyword tools have a bulk manual option at all).