Momi

any suitcase or duffel bag will do just fine; make sure you have a small bag or backpack with you to carry all the things you need to when visiting the sites (guide book, map, bottle of water, etc). I have a Travelon messenger style shoulder bag that traveled with me to 4 different countries already and that I could not take any trip without (I did not realize how good investment this bag was until I got it and started to use it on my trips).A must are the following (especially if you travel in the spring, winter or fall):
- rain jacket with a hood (umbrellas will be useless if there is a strong wind-as it was when we were visiting). I love my 3 in 1 Columbia jacket and I think that a jacket like this is one of the best investments you can make!
- 2 pairs of good and comfortable shoes (you need the extra pair even if the weather is good; your feet may hurt at the end of the day and they may feel much better in a different pair of shoes the next day; just switch the shoes every other day)
- 2 pairs of pants (jeans may not be very practical since it takes a long time for them to dry if you get wet), 4 shirts, 1 sweater or sweatshirt, 1 hat and 1 pair of leather gloves (if you go there late fall or during the winter)

If you go to a concert or a nice restaurant, you may also need to pack a nice dress and a nice pair of shoes, and also a nice pair of pants, light jacket and nice shirt for the man in your lifeTake some basic stuff with you to last for 1-2 days. You can really get all you need while in Rome, but it is nice to have the basics with you when you arrive: travel size shampoo, travel size shower gel, travel size after shave; toothpaste and toothbrush, deodorant.
I also had some Tylenol with us and some TheraFlu (which we had to use, unfortunately, since we got soaked by rain few days in a row and we were getting colds).