I thought the opening ceremonies were ridiculous in the worst meaning of the word, but that's not a specific criticism of the London organizers or Danny Boyle. I just think that Olympic opening ceremonies have continually drifted away from anything even tangentially related to the Games themselves. Instead, we get a spectacle-laden history lesson about the host nation that requires a primer if you aren't a native.
I'm not saying that these nations should not be proud of the things they choose to depict, but the narratives (such as they are) seem woefully out of place and increasingly cryptic. I mean, yeah, the replica of Glastonbury was cool, the industrial revolution bit and how it led to the arrival of the rings was technically and visually impressive, and the Bond/Queen thing was refreshingly informal. But what does all this really have to do with the Olympics? What relation do a celebration of social media or a giant inflatable Voldemort have to the event?
As always, the parade of nations and the torch lighting were the best part because they were relevant. Host nations are free to put whatever they want in the ceremonies - it's their right to show off, and they've earned it. But I would advise them to keep their eye on the prize instead of going too far afield.