Under Geoff Johns, Hal Jordan and the Green Lantern Corps have become the center of the DCU. Yes, bigger than Superman, Batman, and Wonder Woman is the Green Lantern.
Not to mention Superboy Prime
Rescued from the Scrappy Heap: Several heroes and, notably, most minor villains in the DC universe, one way or another.
The Flash had most of his villains redone, starting with a strongly anti-hero Captain Cold, spinning through most of the Rogues' Gallery. Everyone was adjusted and made deeper, with their personal storylines continuing. Perhaps the most drastic change was the death of the first Captain Boomerang and the rise of his son to take his place.
And Parallax. In fact is it safe to admit that he has pretty much made Green Lantern the most consistently good comic of the last 5 years?
In one issue, Johns took the Tattooed Man from a joke to an anti-hero powerful enough to earn his own mini-series. (Admittedly, it took giving someone else the name and powers to do it, but the new Tattooed Man is still awesome.)