I have used a lot of tools for keyword research. Of course I still use Google's Keyword Tool!
Of the paid tools that I have used, I am partial to Market Samurai. I have played some with Traffic Travis and WordTracker too.
I know there are others with different opinions out there and I'd like to provide a thread where people can talk about their favorite tools and why.
Google Keyword Tool:
I like this one because it is free to start with. When I was starting out, free was important. It is fairly straight forward and if you sign in with a gmail account, you typically get about 800 results instead of 200.
I don't think it gives enough information for my taste. Others may disagree with that. I also know that you really need to dig into the information you get to make better decisions.
For Example: You search for a group of keywords and see that according to Google, there is not a lot of competition. You think, "Hey! Why am I the only one to realize the value of ABC?"
Based on that result you start building your niche site and backlinking, only later to find you are up against 30 super-duper authority sites with MILLIONS of backlinks and TONS of PR and every site is at least 50 years old! (OK, maybe not 50 years old, but you get the point!)
You have to know how to dig deeper into the information the Google Keyword Tool gives you.
OK, I bought this a long time ago because I saw that one of the gurus recommended it when I was starting out. Since then, it has become my go-to application for keyword research.
If you apply the same example above, all you have to do with this tool is check the domain competition. That one check could save you a lot of trouble when trying to find a niche.
I also like all of the helpful features for monetizing and domain search. Overall, I could not be happier with the product.
One negative - Sometimes getting the research results takes FOREVER and the program freezes up.
I don't consider myself qualified to go into detail here. I like a lot of things about it for sure. I may report back on my personal finding later.
OK, I do like WordTracker a lot. I think it is really a good tool. My biggest complaint is simply the cost.
You can either argue this way - Yes, it is too expensive on a monthly basis to justify the cost. I can't afford that much! (I generally agree for a newbie just starting out.)
Or you can argue this way - Yes, it is very expensive, but the results and time saved are worth the expense. What is your business worth? (I agree with this assessment too provided your online income is now paying for this tool.)
Anyway, just a few thoughts on a few keyword tools I have had experience with.
Now I know there are TONS of tools out there. I didn't mention more then these four for a reason.
What are you using and why?
All the best...