If it's a hard drive failiure, then you need professional data retreival - costs around $1,000 per megabyte I believe - and that's just for raw data (not your files back) - and they don't guarantee results. I am told that they attempt to mate working parts of identical drives with the platters from your dead drive to read the contents, which sometimes works, depending on what state your platters are in.
Worst is if your hard drive heads have 'crashed' (touched the surface of the platters) - chances are they've torn the surface to shreds, in which case you have absolutely no chance of recovering anything at all from the drive. In any case, it'd probably be cheaper to hire someone to write all your documents again
Hmm, sorry to paint such a gloomy picture... cheer up, there's always song and dance and chocolate biscuits!