In the first episode when Ban wipes out the mooks with his gun fu skills.
Episode 13 is an entire Crowning Episode of Awesome for Doggie. First he throws his shades into the air and transforms into Dekamaster for the first time. Doggie then proceeds to defeat 100 mooks in less than a minute. Later in the episode, he defeats the MOTW with the Dekaranger theme song playing and the other Dekarangers watching in the background.
The 100-man fight was awesome enough that the Super Sentai Artisan release of the Master License allows you to replicate the whole thing, including playing "Dekamaster Never Stop" and all the sound effects!
In episode 23, the main Dekarangers are trying to prove to DekaBreak that Heart Is an Awesome Power. How is it hammered home? They stay there, being struck by lightning summoned by the Monster of the Week (which nearly killed DekaBreak seconds before), and, led by Ban, they summon all their Heroic Resolve to break the attack.
Also, the Riding Dekaranger Robo. That's as badass as it goes.
In episode 26, after getting his ass handed to him in a one-on-one fist fight (he was unmorphed at the time, since they had to infiltrate an illegal fight club), Hoji trains despite his injuries. When he comes back to the fight club for a rematch, he proceeds to completely dominate the fight... until his opponent takes a performance-enhancing drug. He then proceeds to beat the tar out of Hoji, until Hoji gets his second wind.
In episode 29, Tetsu is fighting the Monster of the Week who killed his parents when he was a kid (namely, it was this incident that led him to enter the Tokkyou). When the Judgement is passed on him, the monster tries a last-ditch strike by diving into Tetsu's helmet visor. How does Tetsu respond? By Megaton Punching the monster in the face just an inch before he can enter the visor.
Episode 33 - Things are looking down as both Doggie and Tetsu (Deka Break) have been captured. Suddenly a giant hole is blown in the wall and you see five silouetes behind it. Cue Crowning Music of Awesome as the main heroes step through, debut their shiny new SWAT Mode, and proceed to wipe the floor with the two MOTW and at least 50 goons.
Episode 36 - Not only does Swan transform into DekaSwan, kicking Anaroid ass in true Lady of War style, she then demonstrates why she is the one awarded with being the best scientist/engineer in the whole of the Space Police by performing the calculations necessary to disarm a self-destructing engine in under three minutes...WITH AN ABACUS!
In episode 39 where the MOTW kills victims in the dream world to steal their souls. She did this to Umeko who was there as bait. The awesome part is when Jasmine beats the MOTW at her own game, by showing her a dream in which Jasmine breaks out of the chains of death, blows up a bus with a punch, then sticks up the MOTW with D-bazooka and tells the MOTW "bye-nara." All the meanwhile in reality the Dekarangers have released the souls and Umeko returns back to life.
In Dekaranger vs Abaranger, and also doubling as a Funny Moment, after reading Ryouga's memories, Jasmine imitates the Abaranger theme song "Aba Aba Aba Aba Abaranger."
Let's not forget episode 34, where Sen proves why he's a member of the Special Police. Let's just say the Monster of the Week learned the hard way that if you make him angry, not even invoking Screw the Rules, I Have Connections! will save you. As long as he has received approval to delete you, he'll carry out the sentence before you can get your parents to do anything.
Episode 46 has a similar moment from him. He is so calm, but you can feel the anger rising off of him. He doesn't even proceed to pull out his D-Shot, just punches the guy in the face. Repeatedly. While the other guy has a SWORD OUT.
Sen once figured out how the villain's powers worked while trapped far away, reconstructing the battlefield in his mind and working out what had happened there in the past simply from hearing it described.
Episode 46 has two moments from Umeko. At the beginning, she proceeds to destroy a robot in the name of love. Towards the end, she discovers that the man she thought she loved was a con-man intent on killing her and proceeds to wipe him out...all while clearly hurt. Did I mention that both of those were done singlehandedly?
10 Years After, during the climax battle, Doggie handed down Ban his D-Sword Vega, and he proceeds to slice and dice the Big Bad, and even coming up with his own 'Akaza Sword Style: Lightning Blade'! Total badass
It may also double as a Call-Back to the episode where he found he was related to a member of the Shinsengumi. Still doesn't make it any less awesome.