Left: Top 10 contestant Trent Harmon performs onstage at FOX's 'American Idol' Season 15 on February 25, 2016 in Hollywood, California. Right: Trent Harmon Trent Harmon was the last Idol winner ...

American Idol has been a staple of TV for over two decades. There have been highs and lows, but these are the 10 best seasons, so far.