Personally, I consider these things a bug, not a feature. They're clunky, ugly, and annoying. They were really designed for analogue signals, which makes it particularly unfortunate that most DVI cables seem to have them - I am only using DVI to carry a digital signal, so they are definitely not needed.
The only DVI cables I actually have that don't have these beads on them are the ones that came bundled with my KVM switch - they carry a digital DVI signal just fine. I'd like some advice on how to find some new DVI cables without ferrite beads on them. They all seem to have them (even the cheaper ones) - does anyone know of some that don't?