Keyword Research Tools

I've been wondering about keyword research solutions like SpyFu and KeywordSpy. SEOCorner recently provided a nice head-to-head comparison of the two. I also read this explanation of how SpyFu works and where/why the data might be wrong. For, now, I think I'll stick to my current process. I don't see these tools really helping me out all that much. I'd love to hear real-world stories about how these solutions actually helped someone.