Formatting before selling

[NightShadow]

What software do people use for formatting a hard drive before you sell a PC/Laptop on? Usually I don't worry but this one has had a lot of stuff on it and I would rather it was at least a bit more securely erased than the quick format which Windows Vista/7 does.

 

[NightShadow]

Will check out the suggestions, thanks guys.

Have to say I am not overly paranoid, it's just when installing Windows Vista (as this laptop came with) the format takes all of a few seconds and there is no option to choose a full format like in the days of XP. I know if somebody wants to get to my data there are ways, just looking at making it harder for the average person.