The Forum is disappointing in that it is basically ruins and a lot of it was caused by the Romans themselves as recently as the 30's.
That said a little imagination and you are walking where the Roman legions marched and Emperors ruled.
The sites that you had read about or heard about or seen in films are right there in front of you and make you realise how powerful Rome became and how far they fell.
Wear good shoes and take some water. Take your time and let your thoughts drift back to days of Rome.