To defrag or not to defrag, to stick with Windows native defragger or look elsewhere for a free defragger or buy a defragger is all in the domain of an individual's preferences and perceptions.
How many of us have the ultrafast SSD drives? Until such time these drives come out in as large capacities as the other kind of Winchester drives
and become affordable, many people will continue to use the platter drives.
Given this scenario, I do feel defraggers is a necessity and cannot be wished away.
That Windows 7 does not require a defragger is far-fetched. If it were so, why should MS embark upon providing a much improved Defragger in Windows 7? Disk Defragmentation
I had always gone with Raxco's Perfect Disk for a longtime now and Perfect Disk 11 is what runs on all my machines. I defrag atleast once a week that apart the stealthpatrol mode in which it runs. I care not to quantify whether it has increased my PC's performance and whether it is in microseconds, nanoseconds or picoseconds. If I believe that it does good and am happy with it, that is it.