As we all know keyword research and selection is the main concern of SEO and SEM. It is necessary to know that which keywords are most relevant and the estimation of the traffic these keywords can get you .

below are some of the keyword research tool which you can use for research

Adword keyword research tool
Google Insight
Word tracker
EBay keyword research tool
Keyword discovery

above are the tools I have used so far, If you have used any other tool then give the name in post..

I have been using "Keyword country" and it is like my magic bullet.
It helps me in
-Checking the profitability of my keywords
-Rip my competitor keywords
-Choosing the most targeted keywords
-Finding influential niche related blogs
-Getting alerts when my competitor changes strategy
-Finding LSI, misspelled keywords and much more...

The best keyword research tools I have ever used are "Keyword Difficulty tool" and "SERP Analysis tool" offered by SEOMoz.

I used SEO moz tools. Those are really great. But no compare with free tools.

I think Keyword research tools is the best way to select a particular and best keyword. There are many tools in internet and every one can choose them.

I use Adword keyword research tool.

I have tried lots of tool for keyword research. But finally I feel that Goolge keyword tool gives us lots of ideas. While in other side Word tracker gives us exact searches. Mostly I am using these both tool for keyword research.

According to me, Google adword keyword research tool is best to find keywords.

Google adword keyword research tool is best ....