Out of how many?
Tiberius (nuts, murdered), Claudius (nuts, maybe murdered), Caligula (murdered, definitely nuts), Nero (nuts, suicide), Galba (murdered), Otho (suicide), Vitellius (Murdered), Titus (sickness), Domitian (murdered), Verus (plague), Commodus (assassinated), Pertinax (murdered), Didius Julianus (executed), Caracalla (nuts, murdered), Geta (murdered), Macrinus (executed), Elagabulus (murdered), Severus Alexander (murdered), Maximunus (murdered), Gordian I (suicide), Gordian II (killed in action), Pupienus (murdered), Balbinus (murdered), Gordian III (murdered), Philip I (killed in action), Trajan Decius (killed in battle), Hostilian (plague), and that is just to 251 AD.
You'd have to go all the way to 283 AD (Carus) to find someone not killed in action, assassinated, murdered, or plagued. And he was killed by a lightning bolt.
Or all the way to 305 AD (Diocletian) who retired and later died of natural (purely natural) causes.
As for me, I'd probably go with Harald Hardråde. He died in battle, but his death closed an era. In his day he traveled widely, sampled the very best of female flesh to be found, drank the best vodkas and wines and beers, became the Commander of the Varangian Guard (bodyguards to the Byzantine Emperors), made himself King of Norway, sailed the seas as a Viking, then had a bad day in England trying to become king there too. End of story.
But the life he had while he had it...
[This message has been edited by Terikel Grayhair (edited 10-12-2012 @ 01:06 AM).]