I have years and years of proud character moments, but the first that comes to mind is this:
The halfling pictured above is Gren Tealeaf-Tosskettle. At the time he was a 1st level fighter/3rd level rogue. During their journeys he and his companions (dwarf cleric, dragon-blooded sorcerer, hound archon pup) found themselves facing a rather angry minotaur. The sorcerer and cleric spells were depleted. The party fought bravely and eventually the the minotaur realized to stay would be his demise and he ran.
I was down to less than 20 hit points. A full round of attacks from the minotaur would likely kill me. Still, Gren knew that if the beast got away, he'd cause destruction on the nearby town. He chased the creature down. Using his quick tongue he was able to lull the brute into a false sense of security. I rolled my feint check and scored a critical hit with my sneak attack, taking the minotaur down in one go.
It was a risky move, but it payed off. It's a story that still makes me smile.