Joe Rincon (Hector's father) becomes a Heroic Bystander when he takes down an approaching alien using a discarded M16 dropped by one of the protagonists. And he's had no military or firearm experience, he just picks it up and opens fire wildly. He dies, but it was awesome.
This leads into the final scene, a panning shot over the burning Los Angeles. And then a helicopter flies in. Then another, and another, and another. Complete with radio chatter between all of them as what is soon revealed to be a sizable force of helis and fighter jets fly into view, all heading towards the city. The final line of chatter is the clincher.
"Let's take back Los Angeles."
Nantz gets one when the Platoon question whether or not he truly cares about their safety (doesn't help one of the previous platoons he was with got killed, Lockett's brother included), he finally makes it known he not only regrets each and every one of their deaths, but he remembers their names and everything about them. It's a small scene, yeah, but it shows just how deep Nantz is, and how much it affected him.
Although combined with nightmare fuel, the marines dissecting that one alien was quite awesome.
The entire final action scene, from Nantz's Pre-Ass-Kicking One-Liner - "Let's show these bastards who they're fucking with", indeed - right up to the very end when they take down the drone controller and fight off the aliens protecting it. Perfect climax for the movie, in my opinion.
With Tech Sergeant Santos shooting down a drone with an AT4. That is one hell of a shot, considering the drone is a relatively small, fast-moving target, and the launcher is an unguided, single-shot weapon.
A drone is homing in on the squad's bus via their radio transmissions, and Nantz needs to take it out. He doesn't want to risk revealing their location, so what does he do? Grabs a radio, and plants it at an an abandoned gas station, turns it on to lure the drone in, and blows the whole thing up with a grenade.
During the freeway scene, Nantz and Martinez are setting a trap for the aliens, when the alien Walking Tank severely wounds Martinez and destroys the detonator they were going to use to set off the trap. Martinez goes back to the bus, where he has a bag full of C4, and hides there as the tank passes by, until...
"This is Lieutenant William Martinez, Echo Company, Second Battalion, Fifth Marines! Hoorah!" *BOOM*
The aliens get a few as well - chief among them is a certain point when the Marines think their air superiority will give them an advantage. Turns out they have airships, too.
UCAVs that can fly at Mach 7 and shoot missiles as well as something similar to white phosphorus. And how do they respond to the military's plan to bomb the alien ground troops to Hell? they fight off the jets and then wipe the Forward Operating Base off the map.
On the freeway, the alien infantry has been getting badly hammered by an Abrams tank and Lockett on a Browning M2. Cue the Walking Tank.
During the final fight, one of the aliens gets bayoneted to a wall and fired into by Santos. Skewered to a wall and filled with lead, it punches her.