The father of the field is a guy named John Pendry at Imperial College in London. He could end up sharing the prize with someone else who did clever things with structures—Thomas Ebbesen, for example, who found a way to pass light through holes far smaller than people thought was possible. It's called extraordinary optical transmission and has potential uses in data storage.
The physics gurus over here also keep bringing up something called the Aharonov-Bohm and Berry Phases. These are complex quantum effects I only vaguely understand, so I'm praying it's not those.
Adrian Cho, physics reporter for Science’s news department:
In the past, I've been able to pick people who would win within the next few years, although never on the right year. For example, it was pretty clear that Ray Davis would get it for measuring neutrinos from the sun and that Kobayashi and Maskawa would win it for their explanation of an asymmetry in particle physics that predicts three kinds of quarks. And I did, in fact, ask researchers about both of these possibilities before these folks got the prize. In both those cases, there was an experimental development that made it seem more likely that they would win. I don't have a strong suspicion like that now—the Higgs thing isn't likely to hit this year because nominations closed in February.
If I had to stick my neck out, I would guess Vera Rubin for measuring galaxy rotation curves and inferring the presence of dark matter. She really ought to win one of these years. Chuck Bennett for the WMAP satellite could win, but he may have to wait a while longer, especially as a cosmology finding won last year. Once you get into condensed matter physics, it's a lot harder to predict.
There is also an idea that is so elegant it deserves the Nobel on those grounds alone—John Pendry's transformation optics, which is the theory behind cloaking. Basically, he started with the idea from general relativity that warped space-time can bend the path of light and then figured out a recipe for mimicking that bending by tailoring the optical properties of a metamaterial in unwarped space. The challenge is to actually achieve the spatially varying optical properties required by the mathematical transformation, which so far has been done only imperfectly. But the idea itself is so pretty, it's the kind of thing that makes a physicist's toes curl.
Whatever it is, chances are that after it's given, it will seem like an obvious winner. That's usually the case.
I don't usually engage in the annual speculation or betting pools, but I do follow the discussions pretty closely.
The discovery of the Higgs boson is by far the biggest physics news of the year, but it's probably premature to give it a Nobel. There was a time when the discovery of any new particle was cause for a Nobel Prize. That was also a time when one to three people could make the discoveries; such is no longer the case. The reason this might not win a Nobel Prize is because the prize is limited to three individuals, and thousands contributed to the discovery of the Higgs. That's not even counting all the theorists who first developed the notion—including but not limited to Peter Higgs. Expect this to be a contentious discussion wherever particle physicists are gathered: Who gets credit?
Metamaterials have a negative index of refraction, akin to tossing a pebble in a pond and seeing the ripples move inward instead of outward. This sounds impossible, but it's not. Metamaterials have fascinating optical properties, needless to say, and expect to see them used in lenses, for advanced microscopy, and as cloaking mechanisms to make objects invisible—at least to radar, if not visible light. Those most commonly associated with it are Victor Veselago, John Pendry, David Smith, Xiang Zhang, Sheldon Schultz, and Ulf Leonhardt (who has also done interesting work on artificial black holes).
Photonic crystals are found in nature: opals and butterfly wings are the best examples. But their unique structure makes them the equivalent in optics to semiconductors in electronics. They are tunable, i.e., they only allow light of certain energies to pass through them, and that makes them ideal for practical applications. The top contenders for the Nobel would be Eli Yablonovitch, Shawn Lin, John Joannopoulis, and possibly Sajeev John.