Rome

Rome is internationally known for the Colleseum as well as many other attractions, so if you are able to go, I would highly recommend it. Some tips when traveling to Rome or Italy in general:
1. Mind your personal belongings, there are pick pocketers everywhere. Be careful for people that want to pose in costumes and then charge you for the picture, unless you want the picture.
2. Trying real italian food is a must, true home made italian food you will not get it anywhere else, I don't care what anyone says. Some foods to try are Caprese, this is Slices of real Mozzerella and Tomatoes with olive oil and basil sprinkled. Italian pizza is very good, however very different from American style pizza so keep this in mind when eating it.
3. Having Italian ice cream is a must, this is called Gelato, outstanding, the best ice cream I have ever had.
4. Generally speaking like in other countries, please attempt to speak the language, they will respect you and will be more willing to help you if you try and pronounce their words, so try taking some italian lessons first if you can. Do not talk to them like they should know english, most of them do, however there are a lot of italians that would appreciate if you speak their language, because you are in their country.
5. Go sight seeing as much as possible, learn about the history of this great place, it may be very tiring, but you will never forget your trip to Italy, I guarantee you that.

I just got back from the Vatican and Rome, wonderful place. Most of the sites are very doable on the spot (The Colosseum, The Forum, Spanish Steps, etc. The Sistine Chapel, however, its good to plan ahead. Make sure you wear pants and where a shirt that covers your shoulders. I woke up and got there just before 9:00AM and there was absolutely no line.. except the doors hadn't opened so I ended up walking around the Vatican Wall into San Pietro (St. Peters). It was beautiful and quiet in the morning.. but by the time I climbed the stairs to the top, soaked in the view, and got back to the entrance of the Vatican Museum (entrance to the Sistine Chapel), there was a 2 hour line.. My suggestion is get there before 9:00 AM.. The entrance is right by the exit.. have a guard point it out of the doors aren't open.. It'll give you the best experience..

As for carry on.. I just took a small back pack and I was in Europe for 3 weeks.. but I like the no hassle approach.. if you are sleeping in hotels.. a roll on is ok..

you don't need any travel guide book if you go to rome,just walk around,it's an open air museum which takes you to the times 2000 years ago...