Keyword Research Tools Chapter - 5

http://www.spyfu.com (spy on others campaigns)

http://freekeywords.wordtracker.com (very fast)

https://adwords.google.com/select/KeywordToolExternal

http://www.nichebotclassic.com

http://www.KeywordDiscovery.com (free trial)

http://www.domaincountry.com/

https://adcenter.microsoft.com/Default.aspx

http://www.nichetaxi.com

http://www.vretoolbar.com/keywords/ (Overture based)