Yeah, I’m thinking that’s a bit overkill. But I guess if you truly need a single hard drive to be completely destroyed, a pound of thermite burning at 5000 degrees is one way to do it. Although “burnin’ stuff up good” isn’t necessarily gadget-related, this little how-to at Hack A Day is remarkably thorough in what mixtures to use, how to ignite correctly, how much to make and where to put it in order to make that hard drive go away permanently. I’d set up a couple grams of this stuff inside a laptop or iPhone and have it on a little remote trigger. You could even hack it to play a sound file: “This iPhone will self-destruct in three… two… one…”
They also point to a fun episode of Screen Savers from 2003 where the guys also try the thermite thing to silence a drive, and some Hydrochloric acid to boot. [Thanks for the tip, Jason]