Sticking with unenhanced humans for the moment, historically you have to give it to Oracle.
Calculator was fairly high up on the list for a while.
But seriously, has everyone forgotten Jack Marshall?
I would think....
Terry Sloane
Oracle - Barbara Gordon
Cyborg
Mr. Terrific
Calculator
Batman
Robin - Tim Drake
Robin - Damien Wayne
I think oracle is better than batman. Surprised so many people would say otherwise
Batman is the best at everything, right?
So...
Streaky the Super-Cat. He could chuck hairballs across the solar system.
Just human's:
Oracle
Calculator
Tim Drake
Batman
Superhuman ones:
Hank Henshaw/Cyborg Superman
Engineer
Cyborg
The Hacker Files
Strange little series taking place in the digital backwaters of the DCU, and featuring early appearances of Oracle.