Great draw with lots of options according to my speculations.
I will start with the biggest clash between Milan and barca and of course contrary to many I see Milan winning. The highlights of the clash will be TS owning Messi so hard but that could only mean that barca will increas their interest in the Brazilian for the summer.
Benfica - Chelsea is a tricky one and could go wither way but I want to mention because of the semi-finals. Knowing that I am tipping Milan to reaach the semi-finals, I see two different outcomes. If Benfica play Milan then Milan will easily reach the final however, I see them struggle against Chelsea.
The other side of the tree is somehow easy and we will definitely see a Real - Bayern semi final and the outcome of that will totally depend on injuries and suspensions from both teams. Of course with a slight advantage for Madrid.