It may not be as simple a question as a first glance reveals. Do you think that through some supernatural means, be it God, spirits, or magic, one can alter the laws of physics even for a short period of time? If so, how is this achieved, by your reckoning? Let's take, for instance, the water into wine example of a miracle.
Many LDS people would probably believe that Jesus (and to an extent barring faith, all of us) has authority over atomic structures, and can simply command them to be something else. LDS people believe that the spiritual and the physical are separated only by a matter of "refinement" (spirit being the more refined of the two substances). But I am curious as to how a mainstream Christian, or a Wiccan, or a Buddhist would view such a miracle (pretend it was performed by someone other than Jesus if that complicates the problem).
Or how about when miracles aren't performed, but it seems like they really should be. I'm thinking of hurricane Katrina here. Kit posed the question to me of why a loving god would let this happen. My reply, "When clouds gather, he let's it rain." In other words, I think the powers that be have a vested interest in letting the laws of physics stay their course. But how much prayer, magic, or faith is needed to break the rules? Under what conditions do the powers that be let the rules be broken? Apparently, there weren't enough prayers, magic, or faithful thoughts to save Katrina, but why?
And why do some people claim their faith miraculously healed them of a terminal disease, but tales of amputees growing limbs back seem to be non-existent? If you are using the Judeo-Christian system, you have a couple of excuses to fall on: It was the mysterious will/master plan of God; if something as obvious as an arm growing back happened, faith would be compromised; bad things happen to teach us something.
What about other faith systems, specifically ones without centralized spiritual power? How do miracles work, and under what circumstances are they denied? Please illuminate me in the comments; I look forward to it. Keep in mind for this discussion miracle will mean any bending of the laws of physics as we know them by supernatural means.
Other theories that I can see working: Reality is an illusion, and breaking the rules involves believing in something beyond that illusion.
More to come as I think of em.