I searched around (on internet) for a nice hotel in Pisa, and found it hard to find something nice. I decided on the Minerva Hotel in the end. We stayed here 1 night to see Pisa (I agree one day is o.k. to see the sights in Pisa) before travelling through to Lucca. Nice hotel with a personal touch (chat, pasta present when you leave). We had a quiet room at the back (you hear the birds singing in the morning) and a great shower. Breakfast is also fine. Would recommend it to friends. All the sights are within walking distance (ca. 10 minutes)and the hotel is also conveniently near the train station (but not too near like other, somewhat dreary, hotels we saw).

We stayed 2 nights at this hotel. We found the staff a bit standoffish and were given poor information regarding resturaunts and directions. The breakfast was edible, the rooms clean but small. The shower door leaked, but most of them do! As Pisa is small the hotel is within walking distance of bus, train, and historical district. The problem is the lack of bell hop service and flights of stairs! Of which there was a decided lack of the former and way too many of the latter!

We tried a couple of hotels without luck upon our arrival in Pisa. A friendly receptionist called the Minerva for us and gave us directions. It is well situated near the shopping areas and only 15 mins or so from the Leaning tower etc.
We had been to Rome, Siena , Chianti and San Gimignano before Pisa and unfortunately it doesnt stand up well in comparison to any of the other places.
We wandered off to find a restaurant recommended by the hotel and that was great. It is called Galileo and is worth the effort. It is very reasonable and the staff are great. Our waiter spoke some English which was great as our Italian is not good at all.The food is first rate and the service impeccable.
The Minerva itsself is an old building. We all stayed on the first floor but be warned-they dont have a lift so if you are higher up, you will need light bags or a strong back!
The rooms are clean and average in size. The bathrooms are clean too. the beds are good too. We paid €90 for a double €60 for the same sized room as a single. We were happy with these rates.
Overall I would recommend the Minerva on account of its pricing and staff.
I think Pisa is a city best visited for the Leaning Tower,the Duomo and the Baptistry and then move onwards to stay somewhere more beautiful like Siena, Rome, Lucca or Parma.