I’m with you guys, using a combo of both Google Adwords Keyword tool and Google Webmaster Tools.
All the online tools I’ve used for keyword research are super pricey or inaccurate, and the standalone programs I’ve downloaded that do the same just get blocked from Google after a few minute (“Google has detected unusual amounts of traffic coming from your network”).
The problem I do have with the Adwords tool, is their ‘competition’ value seems to conflict. I’ve seen many keywords that say ‘Low’ competition, yet the suggested bid is $10. If it takes $10 to be a top bid, that’s highly competitive in my book. So I mainly ignore the competition value and just look at the monthly searches.
Be sure to check subtle differences in your keywords, ie plural and ordering makes a difference.
‘computer’ vs ‘computers’
’laptop computer’ vs 'computer laptop’
can be very different.