I asked for and received some suggestions. Those suggestions backed with convincing reasons, like the arguments I received for Agrippa, I added, but the list has grown slowly.
Ultimately, my goal is 100 people, but I'm short by quite a few. Tonight I added a 70th person, Trajan, because I found an article by Mike Anderson that critiqued my choices.
He said I had left out Cicero, which was absolutely inconceivable given my fondness for the orator, and not true, but he was right that I had failed to include Trajan, the important emperor responsible for extending the Roman Empire to its furthest limits and one named the best by his fellow Romans. In my defense, I tried to limit the number of emperors to prevent the Romans on the list from duplicating a list of famous Romans, but I agree, Trajan definitely deserves the spot.
I'm still undecided about Leonidas. He may have been the Spartan responsible for the 300, but is it the stance of the 300 against the Persians or their general that people should know? I'm undecided on this.
Anderson suggests Livy to provide the Roman counterpart to the Greek historians, but Tacitus is there, so I have a Roman counterpart and that argument doesn't quite hold. He also suggests Marcus Aurelius, Lysander, and Isocrates. Remembering that this is not a list for specialists, what do you think? Please post your reasons (and selections) in the comments. Thanks to you and to Mike Anderson.
Update: On the basis of an email, I included Cyrus the Great. Since this is supposed to be a list of more than just famous Greeks and Romans, and since he is important to more than a few people studying ancient history, I had no question about him other than why hadn't I included him in the first place. Nefertiti appears to be someone so recognizable that I decided to include her even though she didn't rule on her own or make a material contribution.