How we cite our quotes: (Book.Chapter.Bekker #s); all Bekker line numbers are approximate, since they are keyed to the original Greek.
Quote #10
If happiness is an activity in accord with virtue, it is reasonable that it would accord with the most excellent virtue, and this would be the virtue belonging to what is best. So whether this is the intellect or something else that naturally seems to rule, to command, and to possess intelligence concerning what is noble and divine, whether it itself is in fact divine or the most divine of the things in us—the activity of this, in accord with the virtue proper to it, would be complete happiness. (10.7.1177a13-17)
We've made it to the big reveal here: the thing that will make us most happy. Aristotle believes since perception (and especially self-perception) is the thing that makes us uniquely human, the part of us that is capable of acknowledging our existence is what will do it for us.
He's cagey about naming the exact part responsible—intellect? Reason? Comprehension?—but it's clear that he's speaking of the activity of the rational soul. The joys of contemplation (and of course, the philosophical life) are the very best thing ever. No bias here—not from a philosopher like Aristotle. (Ha.)