It depends on who you are selling it to. If it is someone you trust, then that is fine. If you are selling it on ebay, then what you posted is not enough.
After you boot to the install disc, you can click on the utilities at the top. This is right before before you install it. Click on the utilities menu and then disk Utility. From here you can format the hard drive. Do the 7 times secure wipe. This will take a LONG time - plan on 24 hours. When it is done close the disk utility and finish the installation.
While it takes a long time, it makes it nearly impossible for someone to salvage any of your data from the hard drive.