I found this Diskeeper Log interesting. One of our Account Managers recently installed voice recognition/dictation software (on August 19). If you follow the daily log reports, you can see the dramatic difference in the daily number of fragments eliminated. Diskeeper went from averaging 3000 fragments eliminated per day to 15,000!
Eliminating fragmentation to get the expected performance from voice recognition software programs is well documented. Here is one good report on the subject.