So now that it been revealed that Danzou had the Sharingan I'm sure that conspiracy theorist won't let that silly Danzou is Madara debate go, so let's discuss the facts presented to us here and not waist further chapter discussions on it.

So far here is what we do know that supports the Danzou = Madara theory:

They both have the sharingan in the same eye.

So far here is what we know that debunks that theory:

Danzou and Madara have opposing goals. Madara want's Konoha destroyed. Danzou protects it through twisted methods.

Madara has had a number of opportunities to kill Sasuke,but hasn't. While Danzou has had a covert mission to kill Sasuke since he left the village, and never wanted Itachi to keep him alive in the first place.

Danzou wants to recover his right arm and eye for some reason, (The eye looks fine to me) and wants to use Kabuto to obtain Orochimaru's research for this goal. Madara could have easily had access to this information while Orochimaru was a member of Akatsuki.

If I'm reading into it correctly Madara is the true possessor of the Gedo Mado statue. Meaning that he had prior knowledge of Yahiko's group, and took measures to use them as early as before Nagato went crazy. The same way that he carefully watched Sasuke's movements before he killed Orochimaru, knowing Itachi's plans and annoying deal to leave Konoha alone. Danzou was on the opposing side of the battle that essentially was the birth of Pain.

In the end if may seem obvious that Danzou is Madara (really... I don't know how it's obvious), but remember all the times that it seemed obvious that Kabuto would betray Orochimaru?