Just got word from the folks who make my favorite keyword research tool (Wordze), that they are offering a very nice little download for free.
You can download Google's top search terms for every hour of the day since Jan 8th 2008. Their keyword tracking software logged more than 90,400 terms since then. You'll get an excel file mailed to you with each keyword, its rank, and time checked since Jan 8th, 2008.
Nice.