I would think it will definitely be less stress on you if you go with external harddrive, hehe.
I have an old Mac G4 that has a hard drive that might die soon. I want to do some more backups of files but I want to use the method that will cause the least amount of stress of the machine's hard drive so as not to hasten its demise. My options are burn DVDs or transfer via USB to external drive. What do you think?