Google is definitely the best way to go, but I also use Rank Checker on Mozilla Firefox. It's a tool that comes w/ it, but in some cases, you might have to install it.
Have you tried with market samurai? I belive that is the best tool and is based on the API availabel from google yahoo etc. Try with more than one keyword tool and take the common results, That will help u.
I think Google is the baseline. However other research tools such as Micro Niche Finder and Market Samurai are still very useful programs. They can help do many additional tasks such as determining if the keywords are low competition and filtering search results. Market Samurai can research all the important information on the top ten search results of a keyword in seconds.
Well, I haven't used nichebote classic before. But I believe you can trust Google Adwords. It is very helpful.