I'm looking for a software that can find duplicate files of all types either locally or remotely (network share). The app should be able to find files not just by name but by "signature" (something like MD5 hash). It should be able to find duplicates even if the filenames do not match but contents are the same (that's where other, more "intelligent" comparison mechanisms come into play).
Please don't post top 5 google searches - I can use google myself quite nicely. This will need to run on XP/2K3, free solution would be ideal, any solution that is licensed should be reasonably priced and if it is commercial solution, it has to be by an established compan, not by fly-by-night company that won't be there tomorrow to support the product.
Thanks in advance!