I would agree with SWGUY here. Using the "linked" product feature enables you to showcase a product across several categories, yet have it "editable" in its "master category".
This allows you to ensure that the "linked" copies assume the content of the "master" copy, the former changing in tandem with any changes made later to the "master" copy".
We have a lot of success with this on one of our food sites, where grocery-type products can be featured in various places within the store. Spices, for example, that can be used in the preparation of dishes such as soups, casseroles, roasts, etc, can feature along-side ingredients specific to these other "genres".
The beauty of a linked product system is that only the master product (the one resident in the "master category" - which you nominate) is edited, and as pointed out, any changes made to the master product are rendered across all linked instances.
If you are selling dvd movies, for example, you could have a genre "category" called "Action Movies", and then, through appropriate linking, feature these in other categories such as "War Movies", "Spy Thrillers" and "Westerns" - and then perhaps go even further by linking to date-specific criteria, "1970's Movies", "1980's movies" etc...
You could even go further... Your "007 Movies" can be a category in its own right, and all the contents appropriately linked across the categories suggested in the paragraph above...