My favorite Dragon Ball character by far. Goku, Piccolo, and Vegeta are all great. But Krillin is a very well rounded character.
He's part of the comedy and tragedy of the story. He's probably the strongest human on earth. He's certainly been there since the very beginning. And I love his character development the most.
A snarky little kid who wanted to get stronger to show up the bullies at his temple, and came to be a rival and best friends with the strongest fighter in the universe. Becoming kinder and stronger all along the way.
He's just really great.