Best programs to securely wipe hard drive data?

I have two Western Digital Black 1tb drives that I want to sell because my computer has limited sata ports and they will be harder to sell in the future when newer drives come out. I want to buy newer, larger drives to replace my older 1tb drives.

I want to wipe the data that is on the hard drives to make the data unrecoverable without damaging the hard drives themselves since I intend on selling them. Does anyone know any good programs that they can recommend to do this?

 

DBan. Try that.

 

Thanks, thats what ive been reading is the best solution but wanted a second opinion.