We all have our favorite Byzantine emperors (don't we?), and mine is definitely the last one, Constantine XI Palaeologus (although he preferred to go by Dragases, which was his mother's family name, rather than his father's, which was, after all, only the imperial family). Here's me with the statue of the hero of the 1453 defense of Constantinople in Cathedral Square in Athens a couple of weeks ago.
Candidly, this is the only Byzantine emperor I can think of that was both noble and an effective leader. In over a thousand years, I can't think of another example of one that was both.