-Second! I second this request. I actually came to the site today to make the same request. I really like CCleaner and Defraggler would be my defrag program of choice if it had this feature. This should be a default option (@ least on primary drive). When that happens I will stop telling people about OIbits' SmartDefrag. Thanks!
My Suggestion: Defrag when PC is idle. This will be the most usefull feature ever. You could add a section under schedule tab that says run when pc has been idle for [Drop-down] minutes. Then you can forget you installer defraggler. Now your defrags would go quietly in the background.