You will need two rooms for a family of 4, so make sure you have enough points. Hotels in Italy are very rigid about the maximum occupancy for rooms.

Your only Category 4/5 option in Rome is the Excelsior (Cat 5). This is a fine hotel, centrally located, with many good nearby dining options. The metro is within a 5-10 minute walk (Spagna or Barberini) and a number of bus lines stop near the hotel on the via Veneto or via Boncampagni. The major tourist spots in Rome are within a 30 minute walk or eaily reached by public transport/taxi. The hotel has a nice health club and a small indoor pool, and is about a 5-minute walk from the Villa Borghese gardens which offer good jogging trails and open space for children to play. Platinum treatment at the Excelsior is spotty...I've been given everything from a tiny room with an interior courtyard view to a huge corner suite overlooking the via Veneto.

You may also wish to consider the Sheraton Roma (Cat 3) if you are short on points. They usually have Cash & Points awards which are an excellent value, or if you are paying for the rooms there is sometimes an offer for a children's room at 50% off, with accompanying discounts on food. This is a standard business hotel but features a very nice swimming pool, tennis courts, and club lounge. There is also complimentary shuttle bus service to downtown and the airport, and the metro stop is about a 10-minute walk away. If you are driving (don't!), the hotel also has free parking nearby. There aren't any really good suite upgrades available, but I've always been treated very well here as a Platinum. The drawback is obviously the location...it's not near anything, and you need to plan for the 30 minute bus or cab ride into town. I've also encountered more than a few dishonest cabdrivers at the Sheraton, who know that your transit options are rather limited.

I've stayed many times at both hotels and they are both fine. If you can afford the points, go with the Excelsior.

In Venice, your options are the Europa & Regina (5), Excelsior Lido (5), and Sheraton Des Bains (4). Note that the E&R is the only property actually in Venice...the other two are located in Venice Lido, which is a 30-minute boat ride away (and are only open during the summer season). All the other *wood properties in Venice proper are Category 6. If you are just going to see the sights in Venice, the E&R is the best choice; if you are combining sightseeing with R&R the properties on the Lido (which are on the beach and have swimming pools) are a fine alternative. Lido is much quieter than Venice and will be more pleasant during the hot summer months, but you don't have the feel of being "in Venice." The Excelsior can be a little more convenient (the free shuttle boat to Venice docks there), but the Des Bains is cheaper, sometimes offers Cash & Points awards, and is closer to the shopping and dining areas of Venice Lido.

For what it's worth, on my family's summer trip in 2003 we opted for the Des Bains on a C&P award. My 3-year-old son and 13-year-old niece had more fun at the pool and on the boat rides than with anything we did in Venice.