Pisa is a lovely little town-stroll the streets or sit in an outdoor cafe and watch the people. In addition to the tower, there is the Duomo (lovely cathedral) and a gorgeous bapistry-in my opinion, lovelier than the more famous one in Florence. There is also an old Jewish cemetary but it has limited hours and is usually locked.
If you have never visited Florence, you might wish to consider it: Da Vinci's David, the main square filled with 500 year old sculpture (famous for the Neptune fountain) as well as the Uffizi Gallery, one of the finest art museums in the world. Gold is cheap at the shops along the river but I found the leather goods to be way overpriced (much better pricing in San Gimingano). Fabulous lasagna a the little restaurant next to the Duomo-famous for its external decoration but I found the inside to be boring.