If you have a desire to sit down on and travel away from Rome, then the train is the easiest way to do so. From the Termini station in Rome you can travel to all important hubs in Italy several times a day, and the prices are quite okay. So, if you would like a day trip to for example Naples you can easily arrange so with a train leaving from Termini. For more information about schedules, prices and more useful info, visit the official pages of Trenitalia at http://www.trenitalia.com/
The largest and most important station in Rome is named Termini, and that is the place as you can change between the two metro lines. For those arriving from the Fiumicino Airport or from the Ciampino Airport, most buses and trains will take you to the Termini station. The name of the station has been given by the name of the district in which the station is located.