Keyword search/suggestion tool?

What's the best (and most cost-effective) keyword suggestion and research tool on the market? Any suggestions?

Thanks!

 

I use wordze for almost all my keyword research.

You can find my review + incentive offer to you @ http://www.jonathanvolk.com/affiliate-marketing/wordze-review.html

Thanks,
Jonathan Volk

 

try SEO Book Tool, http://tools.seobook.com/general/keyword/

 

If you are looking for a free tool, go for Google's Adword Keyword Research Tool. Just type in "google keyword tool" in the search box and it would give you the result.

If you are willing to pay, NicheBot works very well!