If I were in your shoes, I would remove the hard drive and dispose of the laptop ex-hard drive.
Laptop drives are tiny 2.5" jobbies, I'm sure you can find an unobtrusive home for it at the bottom of a rarely used drawer or in your shed/garage or something.
Sure you can get secure erasing tools, but why waste more of your time on a machine you're disposing.
Hard Drives are cheap as chips, so any new owner won't be breaking the bank by having to buy a new drive.
The other thing you could/should do irrespective of whether you choose the erase or remove route is to detach the controller board from the hard drive and dispose of that separately (and remove/scratch away unique ID data and barcodes from the labels on the drive). This instantly removes any "easy" data recovery techniques (i.e. you would have to resort to forensic techniques using expensive kit) because the controller board has drive specific calibration and track information. Obtaining replacement controller boards is difficult enough for those not in the industry .... obtaining replacement boards without any ID information from the labels is neigh on impossible).
Last edited by mixture; 20th Jan 2014 at 11:16.