I've got to disagree with you there. B-movies usually do have bad or amateurish acting but I think that's a side effect of the way they're produced rather than a criteria. For me, b-movie status is all about intent. It should be aiming for a particular genre audience and not be designed to break out of the genre ghetto. So you're right about Donnie Darko, big names and not being a straight genre film mean it's out of the running even if it had cost 50p. It also should be produced for money rather than any kind of artistic statement. Films like The Blair Witch Project have aspirations beyond sitting on the DVD shelves between the other horror films, but a film like Ice Spiders is not going to be winning any awards and it knows it. It's supposed to shift a few units and make a few quid by hitting genre fans' buttons, and that's proper b-movie behaviour.
This is really problematic. There's other reasons people make low budget genre films than money; for fun say, or two get up on the first rung of the film business. But mainly I'm not sure why you're saying that having any sort of artistic pretensions should magically make a film not a B-Movie. Look at films like, say, Zombie or Tombs of the Blind Dead, even early Dario Argento stuff, any of those more atmospheric old european horror flicks. Are they not B-Movies because they try and be a little bit sophisticated? Or what about Japanese films like Tetsuo, the Iron Man or the Guinea Pig series? Back in the day, films like Don't Look Now and The Wicker Man played as B features in the US. B-movies these days, if it's a category that still means anything, are more about playing outside the taste and sensibilities of a mainstream audience. You can have films like Cannibal Holocaust trying to make a serious artistic statement, and it will still be a B-Movie because there is no way most people would even sit through Cannibal Holocaust, let alone enjoy it on any level. In some ways B-Movies have their own aesthetic sensibility, to the extent that you can make films in the B-Movie genre irrespective of their subject matter, hopefully coming up with shit like the better Troma films (Chopper Chicks in Zombie Town, Toxic Avenger) or Attack of the Killer Tomatoes. You can even dress up a bigger budget film in B-Movie trappings, and when done well it'svery good. Rocky Horror and Army of Darkness are perfect examples, as are Buckaroo Banzai and pretty much everything Cronenberg and Carpenter did in the eighties. What defines a great B-Movie, I think, is a sense of fun, as in the creators were enjoying what they were doing and trying to overcome the restrictions of a limited budget and often limited talent to create something that they believe would appeal to people with similiar tastes and ideas as themselves. Thus I would say my favourite B-movies are:
Pink Flamingos
I Bought a Vampire Motorcycle
All Hammer Horror Dracula films from Dracula Has Risen From the Grave through to The Legend of the 7 Golden Vampires
Bad Taste
The Devils
The Abominable Dr. Phibes and Theatre of Blood (which is more of a sequel in spirit than Dr. Phibes Rises Again)
Witchfinder General
Attack of the Killer Tomatoes
Zombie Flesh Eaters
Tetsuo, The Iron Man
etc.
