Thanks for the nice free wipe utility - I was about to start writing one myself until I found yours which had Gutmann's wiping patterns implemented.
While the program seems quite complete and nicely written I think that a library with wiping functions (based on it) might be nice too, so that you can programmatically wipe various files. Think of a Midnight Commander option Wipe file(s) or others like that - any app that deletes files could have this option to wipe first. I might start working on this - what do you think?
Wipe is a good for deleting material that is sensitive or material that say you don't want anyone to be able to find again.
An open, cross-platform journaling program.
A scientific plotting package.