David stands out amongst other depictions because of the simple fact that it is... well.. David. Normally, David was depicted after his fight with Goliath, triumphant of defeating such an opponent, yet Michelangelo decided to show David’s triumph BEFORE fighting Goliath. This was because Michelangelo found that real triumph comes from accepting a challenge against all odds. Michelangelo’s “David” also represents Michelangelo’s home of Florence standing up against superpowers at the time, while being much smaller.
The main difference between Greek and Roman art was the purpose the art was meant to serve; the Greeks had a great appreciation for aesthetic beauty and the philosophical theory behind it. Whereas Roman art was used to illustrate wealth and were more so decorative.