|Whoop - There It Is...|
1.) This is not a discovery, not in any real sense, but rather a confirmation. The Standard Model has been such an accurate predictor of the properties of matter that the existence of the Higgs, as a key part of the Standard Model, is really a near-certainty. Obviously, you can't state unequivocally that the particle exists without actually seeing it, but in terms of breakthrough discoveries the interesting part is not so much the particle itself as determining its mass and characteristics.
2.) We've already observed the Higgs. High energy physics is a statistical process, where you have to see something enough times to determine that it is an actual phenomenon, and not just spurious noise. The Higgs signal was there in the data from last years LHC run at 7Tev, with a confidence of 3 sigmas, or 3 Standard deviations - about 99.7% confidence. However, that's not considered enough certainty in the physics community to make an announcement - for that they need to look at a lot more data and see the event with a confidence of 5 sigmas. But in reality, if something is 99.7% certain, it's fair to say that it's real.
3.) The Higgs is not a Baryon or Lepton - that is, it's not a particle in the sense of a Proton, a Neutron or an Electron. The Standard Model addresses not only the elementary particles, but the elementary forces of nature, and there is a class of particles, called Bosons, that carry and mediate those forces. The Higgs is the most massive of the Standard Model Bosons, mediating the Higgs Field in order to impart mass to matter. In other words, it's not so much "stuff" as it is one of the properties of "stuff".
I very much hope we can get the Higgs announcement behind us now. There is so much interesting physics to be done at LHC, and once we are routinely working with the Higgs Boson we will have a chance to learn how it works, and start working on much harder problems that we genuinely don't know the answer to. LHC will finish it's 2012 run at 8TeV energies, then shut down for a couple years to upgrade the hardware necessary to run at its rated capacity of 14TeV.
These mind-boggling energies will open the way for humans to begin to answer even more fundamental questions such as SuperSymmetry, Dark Matter and someday, maybe, some mechanism to connect Relativity and Gravity to Quantum Mechanics. This represents the highest accomplishment of humans and their governing institutions, the investment of national wealth and treasure into a massive project that serves no profit motive, but unlocks the secrets of the universe for no other reason than the basic human quest for knowledge.
One more thing. In the course of the discussions of the Higgs Boson this summer, you will hear a great deal of discussion of things like string theory and multiple universes. It is very important to understand that, in spite of the way they will be presented, these are NOT science. These are elegant mathematical theories that make no testable predictions and cannot be falsified. They are very smart people noodling about things we cannot know, but they serve no real purpose in the world of science. Despite the convictions of advocates such as Laura Mersini-Houghton, it is by definition impossible to take measurements of something outside our universe.