The countdown of Green Lantern's greatest onscreen moments has concluded, but I would be remiss not to mention some of the runners up that didn't quite make the cut.
In Justice League Unlimited's Kid Stuff, John Stewart was de-aged into a youngling (no, that's not the cool part). For most of the series run, the Justice League series featured a John Stewart with a very practical approach to the powers of the Green Lantern ring. John typically used the ring to construct spheres around himself or his enemies, beam-blasts, and other visually simple devices.
Kid Stuff, the kid Lantern finally got to have some fun with his ring creating all sorts of imaginative constructs including a missile launching mecha. Through the entire Justice League run, this was perhaps the most fun we got to have seeing some of the creative, though not ridiculous, uses for the power ring.
Smallville's 9th season introduced the Justice Society of America, the team of which Green Lantern Alan Scott was a key member. Although the episode focused on some of the other Society member, Alan Scott was given a couple of frames of screen time, giving the hero his onscreen debut.
The episode also put on display key Lantern artifacts such as the power ring, the lantern, and the mask.
Lastly, although the Super Friends series focused on Superman, Batman, Aquaman, and Wonder Woman (before expanding the line-up in the years to come), the All-New Super Friends Hour episode Flood of Diamonds gave Green Lantern Hal Jordan a guest appearance his first such on the long running series.
#25 - Justice League Unlimited: Initiation - John Stewart's new look
#24 - Batman: The Brave and the Bold: Death Race to Oblivion! - Guy Gardner's Lanternmobile
#23 - Justice League of America: Pilot - Doesn't air
#22 - Justice League Unlimited: The Once and Future Thing: Time Warped - Hal Jordan joins the league
#21 - Legends of the Superheroes - Lantern goes live-action
#20 - Justice League: Crisis on Two Earths - Darker shade of green
#19 - Batman Beyond: The Call - Lantern of the future
#18 - Static Shock: Fallen Hero - Hero worshiped
#17 - Batman: The Brave and the Bold: The Revenge of the Reach! - Loads of Lanterns
#16 - The Batman: Ring Toss - Gotham by greenlight
#15 - Justice League: Hearts and Minds - More to the Corps
#14 - Justice League Unlimited: The Return - The Corps is greener yet
#13 - Justice League: The Savage Time - Ringless
#12 - Batman: The Brave and the Bold: Day of the Dark Knight - Guy is the man
#11 - Justice League: Legends - The Green Guardsman
#10 - DC Heroes: Justice League of America: Between Two Armies - Joining the League
#9 - Challenge of the Superfriends: Secret Origins of the Superfriends - Secret origin of Hal Jordan
#8 - Duck Dodgers: The Green Loontern - Looney Lanterns
#7 - Justice League: Secret Origins - John gets the limelight
#6 - Batman: The Brave and the Bold: The Eyes of Despero! - Guy the hero
#5 - Justice League: In Blackest Night - Green Lantern goes mainstream
#4 - Superman: The Animated Series: In Brightest Day - Welcome to the DCAU
#3 - DC Heroes: Green Lantern: Evil is as Evil Does - Green Lantern begins
#2 - Justice League: The New Frontier - Green Lantern leads the League
#1 - Green Lantern: First Flight - Green Lantern takes flight