Keyword research requires using an awful lot of different tools and cobbling things together in a spreadsheet. It would be great to have one tool that pulled everything in and made recommendations. My methodology is somewhere along the lines of:
Do a broad search in Google's keyword tool with "Only show ideas closely related to my search terms" unchecked and only Match Type: Exact checked.
Export to Excel.
Based on traffic volume and my hunches about relevance, choose a lot of keywords that seem like good candidates.
Enter those keywords 5 at a time in SEOmoz's Keyword Difficulty tool and copy the difficult score back to my spreadsheet.
Choose keywords based on some combination of difficulty and search volume.
It would be great to have this in one nice little app. It could work something like this:
User enters keyword ideas.
User adjusts a slider between difficulty and traffic based on the weight they want to give these factors.
App generates a list of keyword ideas, with traffic and difficult listed out in columns.
User thumbs-ups ones they like and thumbs-downs ones they don't like.
App generates new ideas and rankings based on feedback.
I'm somewhat new to SEO, so if my approach is way overly simplistic, oh well. But it would be nice to have something to make keyword research easier and self-contained in one app.