There are four trade paperbacks that comprise the countdown to the Infinite Crisis, the story that redefines the DC Universe. Villains United stands out for several reasons as best of the bunch.
The first is that the story is pretty self-contained and straightforward. You don't need to know a lot of details about characters' pasts or the cosmology of the fictional universe to get what's happening. The supervillains of the DC Universe are teaming up to take down the superheroes, all except for six bad guys called the Secret Six who are being blackmailed by a mystery man called Mockingbird into attacking the Society of Supervillains. The result is a big, action movie ride of a story, where no one can be trusted and you don't know what will happen next. Because these are supervillains and as such they aren't held by the same moral codes as superheroes, so they really are unpredictable.
The second standout detail is that this book is written by Gail Simone, one of those rare female comic book writers who should be more prominent but who also has a control of humour and drama that puts a lot of male writers to shame.
Third is the art of Dale Eaglesham, which is very very easy on the eye. He has to draw literally dozens of different costumes and freaks and it all looks consistent and exciting, which is often lost amongst today's search by artists for realism. Just look at that cover. The work inside, which stretches from the African savannahs to rainlashed docklands to the final showdown at the house of secrets, never fails to convince.
One caveat is that there are some loose plotlines at the end which are to be gathered up in Infinite Crisis, but that does not stop the book being a satisfying read.