Mark Waid’s brilliant Irredeemable is more or less based on a What If question:

What if Superman went mad and became a supervillain?

It’s a close look at the psychology of superheroics, starting from the unexamined assumption in most comics that anyone who gains powers will also have the right kind of personality for being a hero. The Plutonian is a Superman-analogue who isn’t up to the pressure…

…and Incorruptible is a companion series featuring one of the Plutonian’s arch-enemies, Max Damage, who has an epiphany and decides to become a hero in response to the Plutonian’s turn to villainy. His problem is that the only way he can think of to be a hero is to do the opposite of what he did as a villain…

Irredeemable, vol.1
Reprints Irredeemable #1-4 (April 2009 – July 2009).
Begins one week after the Sky City incident.
Irredeemable, vol.2
Reprints Irredeemable #5-8 (August 2009 – November 2009).
Follows on directly from the previous volume.
Irredeemable, vol.3
Reprints Irredeemable #9-12 (December 2009 – March 2010).
Follows on directly from the previous volume.
Irredeemable, vol.4
Reprints Irredeemable Special #1 (April 2010) and Irredeemable #13-15 (May 2010 – July 2010).
Begins five weeks after the Sky City incident.
Incorruptible, vol.1
Reprints Incorruptible #1-4 (December 2009 – March 2010).
Begins 37 days after the Sky City incident.
Incorruptible, vol.2
Reprints Incorruptible #5-8 (April 2010 – July 2010).
Follows on directly from the previous volume.
Incorruptible, vol.3
Reprints Incorruptible #9-12 (August 2010 – November 2010).
Follows on directly from the previous volume; must occur before the events of the next Irredeemable volume.
Irredeemable, vol.5
Reprints Irredeemable #16-19 (August 2010 – November 2010).
Follows on directly from the previous volume of Incorruptible.
Incorruptible, vol.4
Reprints Incorruptible #13-16 (December 2010 – March 2011).
Overlaps slightly with the previous volume of Irredeemable, but mostly occurs and is best read after it.
Irredeemable, vol.6
Reprints Irredeemable #20-23 (December 2010 – March 2011).
Incorruptible, vol.5
Reprints Incorruptible #17-20 (April – July 2011).
Irredeemable, vol.7<
Reprints Irredeemable #24-27 (April 2011 – July 2011).
Incorruptible, vol.6
Reprints Incorruptible #21-24 (August 2011 – November 2011).
Irredeemable, vol.8
Reprints Irredeemable #28-31 (August 2011 – November 2011).
Irredeemable, vol.9
Reprints Irredeemable #32-33 (December 2011 – January 2012) & Incorruptible #25-26 (December 2011 – January 2012).
Incorruptible, vol.7
Reprints Incorruptible #27-30 (February 2012 – May 2012).
This is the final volume of Incorruptible.
Irredeemable, vol.10
Reprints Irredeemable #34-37 (Febryary 2012 – May 2012).
This is the final volume of Irredeemable.