Mixing -- you have got to be kidding!
Firstly, I have an analog collection (vhs, laserdisc) and digital (dvd, bluray), each in separate rooms -- then my dvd collection is divided into feature films, tv series, music/concerts, what I call 'living history' -- documentaries on world events, sports and a section set aside for er, slightly racier fare.
Then -- the feature film collection is divided into movies from studios (Fox, Warners, Universal, Paramount, MGM, Sony etc) in date order (movies from 1910-30, 30s, 40s etc) -- also all the 'indie' movies (from public domain, z-grade guilty pleasure crap, stuff straight from the $2 shop, hundreds of good but mainly bad movies, curiously interesting for one reason or other) -- these movies are set aside on shelves in the back of wardrobes and cupboards.
One section is an entity unto itself -- the work of the classic comedians: Chaplin, Keaton, Lloyd, Laurel and Hardy, the 3 Stooges, Abbott and Costello (theatrical features only, I have their tv work is in the tv series section), the Marx Brothers, Jerry Lewis (with and without Dino) -- when I'm feeling down, I usually make a beeline for this section.
I try to mix in the special edition box sets with the rest of the dvds in their date order--these movies were landmarks and certainly stand as landmarks in this collection (especially with the size of those boxes)
I've only swiched to bluray in the last year or so since player prices have been going down and will only buy movies that are favorites of mine, period -- anything else, I'll only get cheap and only on dvd. I have the blurays in a separate bookcase, the dvd versions of the same movie have been put out of view, but like the laserdiscs, kept for future reference.