You might also do some comparison pricing on www.hrs.com It's the site that the German rail system uses on its website (at least they used to use it, don't know it that has changed recently).

We usually end up reserving thru venere or hrs or directly with the hotel--whichever gives us the best deal. The hotels we've booked thru hrs all have had same day or 24-hour cancellation.

Just a quick comment on Hotel Miami. We stayed there in July 2005 (group of 6) and it was good. It was a nice clean hotel, very friendly staff, good breakfast each morning. All 3 of our rooms were good sized with very nice bathrooms.

Some people say it is to close to the train station but we found it very easy to walk to all the sites in just a few minutes. We even had a 3 year old in tow who had no problem walking from the hotel to all the sites each day.

Try Hotel Santa Maria in Trastavere.
Check ratings on TripAdvisor.com.
Was there 3 years ago and loved it. Out of hustle and bustle, but walking distance (or streetcar) almost everywhere. Great little neighborhood teeming with cafes, shops etc.

Thanks to all for your responses. There were some great suggestions. My friend bid our rooms on Priceline and we are at the Hotel Kennedy at a price of $179.00 US per night. Trip Advisor and other sites have mixed reviews of this hotel, primarily due to it's location. We are going to take the attitude that our experience will be with the 50% of the positive reviews and enjoy the $$ saved since the cost is about 1/2 what we would have paid elsewhere. I'll report back when we return in May!

You are saving about $15.00 per night by using Priceline for this location.

According to the hotel's own website, rooms in May our 149 Euros.