Agree - cost/benefit not so hot for defrag
In the old days, defragmentation was key because disks were small and space was at a premium, meaning that new files and programs didn't always have enough room to put the entire file in one contiguous area on the disk. This meant extra seek/read time when retrieving the file and extra wear on the disk servo and read/write heads (yeah, I used to BUILD hard drives). This is much less a problem now (except for the windows SWAP file, which REALLY should be its own partition like *nix) because disk sizes are so much larger, there is better error control on both the hardware and software end of things, and seek times are generally faster (unless you are using a 5400 RPM disk).
You can defrag if you want, but I usually find that simply cleaning up the startup area to remove TSR's (that's Terminate and Stay Resident for you non-DOS people). Get rid of things like Updaters (Google, Apple, Adobe, Java, etc.), printer tray icons (HP is notoriously bad for these), and other startup items and you'll find your PC's startup time dramatically reduced. msconfig is a great tool for seeing what loads on startup, but it isn't so great on disabling/removing things (hint to Microsoft!). IMHO, I can take 5 minutes to clean up the startup on someone's PC, another 5 to look at installed programs, and 5 more to disable unnecessary services and it is a significant improvement, whereas defrag takes hours (days on the ultra-large 500GB+ hard drives) and I rarely notice much of a difference.
