There is a tremendous difference between the popular definition of a miracle in our culture and the narrow technical definition of a miracle that theologians work with in their science. We can often have serious communication problems when people ask me whether I believe that God is doing miracles today.
If by a miracle we mean that God is alive and well and running his world by his providence, affecting the course of human events, then by all means God is doing those things. If the question is asking whether or not God is answering prayers, then I would say emphatically, yes, God is answering prayers. If people are asking whether the providence of God is bringing extraordinary things to pass today, I would say absolutely. Does God heal people in response to prayer? I would say yes to all of those questions because I'm convinced that God is alive and well and doing all of those things.
If we define a miracle as a supernatural work of God, then I would say that God certainly does supernatural works today. The rebirth of a human soul cannot be done by natural means; only God can do it through his power, and God is certainly doing that every day. If that's what people mean by a miracle, then God is doing miracles today. Some people define a miracle so broadly as to say that even the birth of a child is a miracle because it's a marvelous thing that couldn't happen apart from the power of God. So they would define a miracle as any wonderful thing that happens by the power of God. If that's the definition of miracle, then again I would say that, absolutely, God is performing them today.
However, we may be speaking of miracle in the technical sense of an action performed against the laws of nature—God circumventing the very laws he put into motion—for example, bringing life out of death or something out of nothing, such as Jesus raising Lazarus from the dead when his body was in a state of decomposition after four days in the tomb. No, I don't think that God is doing that kind of miracle today.
I certainly believe God could raise every human being in every cemetery in this world today if he wanted to. But I don't think he is performing those kinds of miracles today. The chief reason he did those things in biblical days was to certify revelation as divine—to back up what he spoke with evidence of his authority. Since we now have the Bible, other, miraculous sources of revelation are no longer necessary.