When I'm doing my KW research I use market samurai. Every ow and then I find a good KW that looks like it will be hard to get and like you, at the same time a KW that would be easier to get.
Then using MS I'll check backlinks and even if the harder, higher traffic KW has way more links every now and then when I run the backlink checker it will show me that the page has very few, if any, links using the exact KW I want to target. That tells me it will be easier than I thought to get that KW to the front page of google.
Aside fromm being here the two best purchases I bought on the net were Web Position which was revolutionary at the time and enabled me to kick competition butt. The other is Market Samurai which allows me to do the same thing.