I'd like to say that monster movies traditionally had a sophisticated sense of suspense and restraint, and that the modern CG movie has ruined that. But let's be honest, monster movies have always been extremely dependent on special effects (even before the computer got involved), and they've always been about as sophisticated as a steaming pile of poo. However I do think that modern moviemaking technology has led to showing off the monsters too often and too early. The movie makers are no longer worried about you noticing that it's just a Dude In A Suit, so they justify ramming their overly glossy 3D animation down your throat.
Enter Cloverfield, modern monster movie brought to us by Lost's J. J. Abrams. And you know what? It's good.
The twist to Cloverfield is that the entire film is experienced through a camcorder held by one of the characters. As a viewer you're never yanked from that single storyline. And, more importantly, you're never granted a viewpoint beyond what the characters would experience. It's very immersive, if sometimes a bit nauseating due to the shaky camera work. The result is that the moments when the monster is obscured seem contextually appropriate. It's the result of panicked amateur camerawork, not an arbitrary restriction in an otherwise cinematic wide-angle production.
Cloverfield has all the ingredients of a good monster flick: a cool monster, lots of mystery and suspense, and key characters dying left and right. Which is important, because as far as I'm concerned It's just not a real monster movie if everyone survives intact. Seriously, no happy endings allowed. I'll accept bittersweet, like when the survivors struggle between feelings of both victory and loss. That's fine. But if the entire cast is all alive and well (covered in soot, grime, and blood, of course), then that's just not good enough. I demand a sacrifice!