Just Business. A gunfight and an on-rails motorcycle chase come together to form one of the most memorable missions in the whole series.
Reuniting The Families. The Grove Street gang decide enough is enough and they must get the families back together to push the Ballas back. The meeting goes to shit when SWAT shows up and CJ stays behind in order to rescue Sweet while Ryder and Big Smoke ditch him. CJ fights his way through the motel by himself, finds his brother, and they attempt to escape, but a police chopper shows up. What does CJ do? He shoots it down with nothing but a machine gun. Ryder and Big Smoke come back to save CJ and Sweet and the gang drive wildly through the streets to shake the cops while you pick them off through the roof of the car. Cops try to jump onto the hood of the car to punch you in the face, Big Smoke drives through a freaking car wash to blind the cops, and the gang plays a game of chicken with a low flying helicopter that tries to slice you up with its rotor blades. Big Smoke describes it best at the end:
Big Smoke: Shit! That's gonna be a hell of a story to tell when we passin' the blunt!
Burning Desire. Yes, CJ did start the fire at the Vago's house in the first place, but rushing in a crumbling building to save Denise from a fiery grave was still very heroic of him.
End of the Line. There's the one-man raid on Big Smoke's crack palace, and most notably chasing Tenpenny - who's driving a damn fire truck, mind you - as Sweet desperately hangs on to the ladder, not about to let him get away with everything he's done. And after having Tenpenny torment you and your loved ones for about the whole game, forcing the corrupt bastard off the bridge overlooking Grove Street is immensely satisfying. Even with the release of Grand Theft Auto IV, it's still the most exciting end to a GTA game yet, and debatably the most satisfying until Grand Theft Auto Vand itsOption C.
From the LP: Tenpenny decides to have Sweet beaten up while in jail. Toreno, who in the LP is a god-tier Magnificent Bastard, calls him and tells him to knock it off, demonstrating he has power and connections Tenpenny can only dream of.
The ultimate Moment Of Awesome however, is the story how Sweet put the Families on top of Los Santos. Read everything here.
Is no one going to mention the final mission before CJ is forced to leave Los Santos for the first time? He's just found out from Cesar that Big Smoke and Ryder have betrayed him to C.R.A.S.H. and he's come to the all out war zone between the Ballas and the Grove Street Families only to find Sweet injured and the police closing in on him. Something inside him seems to snap and he annihilates the Ballas as he pops out of cover, fueled by rage and grief.
YO! BALLAS! I'M TAKING YOU MOTHERFUCKERS! YOU HEAR ME?! I'M TAKING YOU ALL DOWN, BITCHES!