Some Helpful Tools For Keyword Research

http://www.google.com/trends/
http://www.marketsamurai.com/
http://www.google.com/shopping
http://www.shopping.com/
http://www.ebay.com/
http://www.amazon.com/
http://shopping.yahoo.com/

From Web Analytics & WMT’s

*Important

Don’t forget to take keyword ideas from Instant Search and also from  related search query at the end of the Search result page(If any)

http://ubersuggest.org/

http://tools.seobook.com/keyword-tools/seobook/ - make a free account to try

keywordeye.co.uk  - make a free account to try

http://www.semrush.com/ - make a free account to try

http://www.keyworddiscovery.com/ - make a free account to try

http://www.keywordspy.com/ - make a free account to try

http://www.wordtracker.com/

http://www.wordstream.com/

http://www.soovle.com/ - collects data from major search engines

http://www.woorank.com/ - Good to try, gives you a lot of info about your site

http://www.spyfu.com/try-it-free.aspx 

http://www.adwords.google.com - GAKT – Google Adwords Keyword Tool / Keyword Planner