raxco perfect disk is pretty good, I tested out their trial but I didn't want to pay for it.
In fact, I believe that the defragmenter that comes built into windows vista is pretty good except that it should tell you it's progress so you know either what percentage is completed or the estimated time to completion of the defragmentation process.
And gladly, windows vista's defragmenter has an autopilot option so it automatically defragments on a schedule you can set up.