Best examples of "secondary" or "lesser" characters best moments.

[sun tzu]

In "Detective Conan" ("Case Closed" for you Americans out there), Kogoro Mouri is, without even realizing it, a fake great detective: He always falls for the fake alibi, always jumps to conclusions, then Conan sedates him, solves the case, and makes it look like Kogoro figured out everything. He's buffoon, really.
But then...every ten or fifteen books...Kogoro actually gets a mystery where he's sufficiently motivated to actually think. And when he does, he becomes a fantastic detective, almost as good as Conan himself.

[Dark Soul # 7]

In the second seasons of Power Rangers the team was confronted by a monster that could erase their memories and thus deactivate their powers, somehow. He manages to do this to the entire team and they're left helpless in their confusion. But then Bulk and Skull, the two comic relief bullys of the series, appear. They've figured out how to reverse the power but they need to get the monster to activate the power that does it. With their own safety at risk they challenge the monster to a western style duel and manage to give the rangers their memories and powers back but lose their own memories of who the rangers are.

Bulk and Skull actually had quite a lot of these. The most famous one being when they take a "I am Spartacus" kind of stand against the world wide alien invasion, spurring the citizens of Angel Grove to do the same. It was awesome.

[dupersuper]

Elongated Man tricking Faust
Elongated Man punching Sonar

and...

[master of read]

ussop, despite being the weakest of the straw-hats, gets his bad ass moments here and there, but they are worth it.

[master of read]

In the second seasons of Power Rangers the team was confronted by a monster that could erase their memories and thus deactivate their powers, somehow. He manages to do this to the entire team and they're left helpless in their confusion. But then Bulk and Skull, the two comic relief bullys of the series, appear. They've figured out how to reverse the power but they need to get the monster to activate the power that does it. With their own safety at risk they challenge the monster to a western style duel and manage to give the rangers their memories and powers back but lose their own memories of who the rangers are.

Bulk and Skull actually had quite a lot of these. The most famous one being when they take a "I am Spartacus" kind of stand against the world wide alien invasion, spurring the citizens of Angel Grove to do the same. It was awesome.

and during zeo, when they took on a group of cogs and saved the rangers again. you know, for bullies, bulk and skull were surprisingly noble.

[master of read]

and since someone named tails, he's actually pretty damn big in the comics. turns out, tails is "the chosen one", the prophecized hero of reality. that's right. not sonic. tails.

and he did save all reality.

[Iron_twister]

Gonna say Wedge Antilles in the films, not counting the EU.

Little screen time compared to the heroes...Does awesome crap in three battles where he could have easily died and arguably wouldn't be missed too terribly.

-Literally blasts through a Tie Fighter to save Luke
-Took down an AT-AT
-Proceed to help destroy the second Death Star with Lando.

[Beadle]

Gonna say Wedge Antilles in the films, not counting the EU.

Little screen time compared to the heroes...Does awesome crap in three battles where he could have easily died and arguably wouldn't be missed too terribly.

-Literally blasts through a Tie Fighter to save Luke
-Took down an AT-AT
-Proceed to help destroy the second Death Star with Lando.

Only pilot to get through all three of Yavin, Hoth and Endor battles. Frickin' hero.

As for other options....

Other than the aforementioned Brenda/Paco stuff (which I remember thinking was just awesome), I always find it difficult to get past Rick Jones in stuff like this.

- He caused the founding of the Avengers
- He ended the Kree-Skrull War.
- He beat the Dire Wraiths with ROM.
- He brought his own wife back to life.
- He organised and sponsored Excelsior (later Loners).

Not to mention all the other things he's been central in (Banner becoming Hulk, Rick being Cap's new Bucky, partnering with the two important members of the Vell family, Avengers Forever etc, etc, etc....). Dude is just the best supporting character in history, and usually all he wants to do is play guitar.