Like my 500 or so CDs, arranging DVDs to achieve some degree of retrieving convenience is a headache at the start but after a while I get used to it.
I classify my DVDs as follows;
(1) Jazz, Pop Concerts & MTVs - and among them alphabetically by artist.
(2) Classical Symphonic performances - among them alphabetically by composer
(3) Animation and Kidstuff (Mullan, Toy Story, Cats & Dogs, Stuart Little) - no particular arragement within coz there's only about 30 of them
(4) Warner Bros (snapper case - looks nice in a row) - no particular arrangement as I have only about 30 of them.
(5) Action blockbusters (sequels together)
(6) Sci-Fi (sequels together)
(7) Drama (contemporary & period)
(
Comedy(contemporary and period)
(9) Musicals (very few)
(10) Oldies (mostly 40s and 50s, just starting)
Having this in mind, its difficult to be strict about this. Like AI which is both drama and Sci-fi. And some like AMADEUS is both drama and musical. Perhaps as my collection further grow I might add OSCAR winners (like BEN HUR, UNFORGIVEN, the Godfather), Period classics (like BARRY LYNDON and THE LAST TEMPTATION). And among those in snapper case, there's a mix of these. Actually, I could think of a lot of classification and end up with just 2 titles or so for each. So far those are the ten classifiations I have for which I use some very heavy object/figurine/vase as separator on the shelf. Looks nice from a distance.