if the new owner of your drive is a 'complete noob' then a quick format will suffice if you feel they wouldn't care or know how to recover data.
or to be sure, to be sure (well, OK, just making it a lot harder) doing a low-level format (not a Quick Format) will achieve the same results as wiping the drive with CC.
the overall time taken may not be much different though, but from memory, the last time a formatted a 500gig HD I seem to recall it took about 2'ish hours.
Going to try a 1 pass wipe on a new 500 GB drive and see if it is any quicker. Will compare to a a low-level format. I have a number of drives I want to sell off.
Yes, as Mta says a low-level format will overwrite all the sectors with zeroes. This only applies to Vista onwards, XP doesn't do the overwrite.
I would think that the format is faster than running CC. CC (using drive wiper erase function) will run a high-level format and then allocate and delete files, whereas a ll format just gets on with the overwrites as part of the format.