Format HD then Erase Unused Disk Space



I was wondering if I want to Erase my Hard Drive to sell, If I reformat my drive using Maxtor Software and then Right-Click and Erase unused Disk Space with Eraser, is that good enough?...should I use DBAN with an already empty re-formatted Hard Drive?...thanx..
It would be better to wipe the drive with DBAN first and then format it, if you want to.
Because DBAN is designed for overwriting the entire hard drive (when you want to sell your computer to simply throw away the drive), while Eraser is designed only for overwriting files or unused disk space.
I'm curious, is there any part of a HD that DBAN overwrites but that format-then-erase-unused-space would miss?