Great cruise with a great itinerary! I did a thorough review of the cruise that you can find at
http://www.cruisereviews.com/Celebrity/Millennium43.htm
I really liked the Claris Hotel for a couple of reasons. First, it is out of the tourist crush that you will experience if you stay in the Las Ramblas / Gothic districts, yet you can walk to everywhere in Barcelona. Also, the rooms were generous in size and the included breakfast was superb. Plus, there is a Starbucks only a couple of blocks away.
Enjoy the cruise!
Tom