I'd have to be completely filled, and depends on how fragmented. I defrag my 60 like, once a week or so. Doesn't take more than 30 minutes, but I don't time it either. I used Norton Systemworks 2002 Pro (Speed Disk) to defrag.
Using DiskKeeper might help a lot. On a 20Gig drive using Diskeeper and a NTFS partition, it takes about 10 minutes tops. Now, if you were using Linux, you wouldn't have this problem now would you.
It puts all of your files in line (on your hard drive's disks) so when you go to access files, it doesn't have to jump around on the disks to find the info, cuz it's all in line
Think of it as a desk that messy, and a desk that's clean. Which would you rather have?
Linux hates me. I changed the resolution. It doesn't like that resolution. My monitor "refresh rate error". YAY! (and i have put my video card drivers on)
My 60 gig doesn't take long at all to defrag, but that's just because I never have enough files on it to take up that much space. What makes defrags take a long time is filling up the drive and then cleaning it out, then filling it up again and cleaning it out again... all the files shifting around get left on remote parts of the drive. I don't have a whole lot of major disk activity, so I never really have to defrag.