O'Neil has spent most of the movie depressed over the death of his son, so he's been reluctant to really get into it. Thing is, he's played by Kurt Russell, so we spend the whole movie just waiting for him to bust out. Finally, during the third act, it happens. A caravan comes to Ra's temple, and the Horus guards are checking everyone, pulling back their hoods. We see villager after villager...and then one of them turns out to be Jack, who points an MP5 at the guard.
Also from the original movie, Kasuf leading the villagers at the end to finally rebel against Ra's rule. I have no idea what the hell he's yelling on top of that hill, but damn if it isn't awesome.
According to the novelization, he is reciting a prayer of praise for Ra in a tone that makes it clear he does not believe a word of it anymore.
Daniel's getting Shau'ri to a sarcophagus and nonchalantly turning around to blast Ra with a staff weapon was pretty darn awesome too, especially considering where he started at the beginning of the movie. Dude doesn't lack bravery.
In the novelization, in the scene where Ra is trying to torture Daniel to death with his hand device, Daniel instead grabs Ra's arm in order to make sure he can't pull away when the ring transporter activates. Ra ends up minus a hand for his trouble.