Wierd to see Constantine and Justinian left off the list of great emperors.
What list is this?
Oh, yeah... [blush]
Vespasian, Trajan, Hadrian, Marcus Aurelius and Septimius Severus are pretty good choices IMHO, although I'd dump the ass-ranger bone-idle bum Hadrian, and the proud Carthaginian Septimius Severus, whose short dynasty ushered in the Crisis of the Third Century.
The term "Five Good Emperors" is old, and consists of Nerva, Trajan, Hadrian, Antoninus Pius, and Marcus Aurelius -- sometimes called the Adoptive Emperors, and nearly the same as the Nerva–Antonine dynasty, the two at the end being Lucius Verus and Commodus, who were the "Two Not-So-Good Emperors".
There's been research into the nature and extent of the pandemic that busted up the party during the reign of Marcus Aurelius. Direct seagoing contact with the Han court of China happened under Marcus Aurelius, and the Han dynasty was having its own problems. Attempts to create a cooperative arrangement and military alliance against common enemies of Rome and China came up that time, but never came to fruition.
Suetonius' "The Twelve Caesars" covers Julius Caesar, Augustus, Tiberius, Caligula, Claudius, Nero, Galba, Otho, Vitellius, Vespasian, Titus, Domitian, with the first six being the Julio-Claudian dynasty, the next four being from 69 AD "the year of four emperors" (and apparently the birth year of Suetonius), and the final three being the Flavian dynasty.
Justinian married a courtesan, aggrandized himself with construction and conquest, carried out the Nika riot massacre, and created a mountain of war debt and taxation that poleaxed the Byzantines. Procopius left behind his secret history in which he gives us a candid view of Justinian, among others.
Badass of the Week picked Boris the Bulgar Slayer, a great choice for best Byzantine emperor. BLUE LANGUAGE WARNING.
Among the Roman emperors, in no particular order, I'd list Aurelian (got a lot done in five years), Diocletian, Vespasian, maybe his son Titus, Trajan, Claudius, Augustus, Julius Caesar, and cheating a bit, his predecessor, imper iter Pompey the Great. In the so-called republic period, Scipio Africanus. I might even throw in some meatballs, like Maximinus Thrax, the schismatic Carausius (thanks to Rosemary Sutcliff), and Magnus Maximus (thanks to Mary Stewart).