My macbook (feb 2008 white) sold on ebay, but I haven't shipped it yet. I'm concerned about my privacy. I can't wipe the hd clean because I sold the computer with valuable software on it. What files should I remove so that the person who receives the computer can't log into my accounts? And what other things should I do to ensure my privacy is safe?
The simple solution
Create a new admin account, then use it to delete your personal account(s).
When you delete a user, you have the option of performing a "secure erase" on their home directory:
Assuming you haven't stored any personal files outside of your home directory, this will do the trick.
The paranoid solution
If you want to be really thorough, the only way to ensure that none of your personal data remains is to securely wipe the drive. You can do this from Disk Utility by clicking "Security Options" on the "Erase" tab:
After that, reinstall your applications. None of your personal data will remain.
Here is another way to do it:
As all the old user's file are encrypted and then erased, even if those files are restored they would be useless without the encryption key.
This solution assumes that no software is installed as "for this user only" as that software would be removed with the old user.
Here is one way to do it: