We're in Rome for 4 days. The first day we're there is our first day in Europe so we're not planning on doing anything stressful as we think we'll just be too darn jet lagged.
The second day is going to be Ancient Rome day. This includes the Roman Forum, the Colosseum, the Panteon etc.
Day three will be the Vatican district. Yea... too much stuff to list there!
Day four, we're only in town long enough to crab a cappuccino and then we have to board our train for Venice!