The most important process in PPC keyword analysis is to find the reliable sources where you can get full list of the business relevant keywords. Usually I am using Google keyword tool, but when you have a large Google Adwords account then you should think about other sources as well. So after doing some research in the keyword arena I have found some resources I would like to share here.
www.keywordspy.com
wordstream.com
spyfu.com
http://www.keywordspy.com
AdGooroo.com
freekeywords.wordtracker.com
tools.seobook.com
keyworddiscovery.com
ispionage.com
keyworddiscovery.com
searchmarketing.yahoo.com
optify.net
webceo.com
positionmonitor.com
https://adwords.google.com/select/KeywordToolExternal
https://adcenter.microsoft.com/Default.aspx?RURL=https%3a%2f%2fadcenter.microsoft.com%2fresearch%2fKeyword
Research.aspx&reason=1
http://freekeywords.wordtracker.com/
http://www.google.com/trends?
http://adlab.microsoft.com/Keyword-Forecast/
http://www.facebook.com/
http://trendistic.com/
http://www.seomoz.org/labs/blogscape
http://news.google.com/archivesearch?
https://adwords.google.com/select/TrafficEstimatorSandbox
http://www.semrush.com/
http://searchanalytics.compete.com/