Yes that data is certainly still there, it's actually very difficult to completely erase data- it leaves a physical impression on the disk even when it's been erased. If I were you, I would yank the hard drive, and give it [the computer] to a local school for parts... There are also places on the internet to do this sort of thing. You're not likely to recover much if you pieced it out on eBay... but you can get a kit to actually *turn* the iMac into a real aquarium 
http://www.redlightrunner.com/macaquariums.html
as an alternative to destroying the hard drive, you could get an external case for it, and continue to use it-- as a plus you'd have access to all of your old data... This is, of course, assuming that the disk wasn't the problem with the iMac dying
pnw
http://www.redlightrunner.com/macaquariums.html
as an alternative to destroying the hard drive, you could get an external case for it, and continue to use it-- as a plus you'd have access to all of your old data... This is, of course, assuming that the disk wasn't the problem with the iMac dying
pnw