NONFICTION
Modulations
Gives a rather abridged explanation of the history of Electronic music. Goes over such topics as the very beginning of Electronic music: invention of the Moog synthesizer, Pierre Henry and his concept of musique concrete, Karl Stockhausen, John Cage; the birth of House music in Chicago and NY; the beginning of Electro (Kraftwerk, Bambaataa); and much more. There's even a book that goes along with the documentary, which I recommend over the DVD.
Scratch
Explains the origin of turntablism and the scratch. Interviews dozens of stars including Q-Bert, Mixmaster Mike, etc.
Better Living Through Circuitry
Not the best documentary out there, but very enjoyable nonetheless. Features a wide range of interviews with all the people involved in the rave scene: party-goers, promoters, and the DJs and artists themselves. You get to hear from Crystal Method, BT, Kraftwerk, DJ Spooky, Meat Beat Manifesto, Electric Skychurch, and many many more.
Intellect
If nothing else, the second disc of this DVD has a really great tutorial for bedroom DJs. Nigel Richards gives his own tips and tricks on DJing (beatmatching, marketing yourself, etc), he's quite the character! The first disc is chock full of interviews with stars such as Miguel Migs, Phil K, Paul van Dyk, etc. etc. etc. Each give their own insight on being a performer.
American Massive
Released off Moonshine Records, this gives you the perspective of certain Moonshine artists that were on the Overamerica Tour a couple years back (Keoki, Dave Aude, Micro, Frankie Bones, etc). Not highly recommended as the DVD's main purpose is not to teach you something about Electronic music but rather to promote the artists on the Moonshine label.
Global Underground: Transmission 001
Probably my least favorite documentary related to Electronic music. Similar to American Massive, it follows around famous DJs while they're on tour, only this time they're British and on the Global Underground label. If you're big fans of Sasha, Danny Tenaglia, Dave Seaman, Nick Warren, etc. you might be thrilled to see these guys speak on camera. Otherwise, the content is relatively poor. There's a Transmission 002 but I have not seen it.
Maestro
To be released in August. I have not seen this but am looking very forward to it. Maestro explains the origin and history of House music. My guess is that it will feature interviews with DJs primarily born and bred in Chicago and New York.
FICTION
Groove
Follows the adventures and misadventures of four average middle-class people at a rave. Each are at different levels of experience with the rave scene: the newbie, the two regulars, and the girl who is ready to move on with her life. Takes place on location in San Francisco. Features a John Digweed cameo. Fantastic soundtrack!
Human Traffic
Soundtrack provided by Pete Tong. Five youthful British clubbers embark on the ultimate weekend experience. This is like the UK version of Groove, only much funnier and light-hearted. Features a Carl Cox cameo.
Go
The rave in this movie is not really the plot's focus but, rather, acts as a backdrop. Very well written and directed, the stories of the characters intertwine into rather hilarious situations.
... I'm sure there are dozens of more movies related to Electronic music: Stark Raving Mad, Party Monster, Rise, It's All Gone Pete Tong, etc. I haven't seen these or heard anything about them so I can't give an honest opinion.