Museo Nazional de Arte Clasica Romana (Roman Art) has some mighty fine statues
The Museo Nazional de Arte Clasica Romana is across the street from Termini. It houses a fine collection of Roman era sculptures on the first two floors, very professionally exhibited with excellent English translations. The top floor houses wall paintings from Roman era villas, many of which are in amazing condition. There are also some excellent examples of mosaic art. Here are some examples.