Southampton (London), England - We did the RC excursion to Windsor & LHR. Since a basic shuttle was $90, this was a good value at $120/person. I'd buy in advance since it did sell out once on the ship.
San Juan, Puerto Rico -
Philipsburg, St. Maarten - Rather than take a taxi, we walked into town. It was a mostly shaded and had a sidewalk, probably 1.5 miles and on the level. We are walkers at home so the it was an easy walk for us. Good variety of shops right at dock but prices were cheaper in town.
Nassau, Bahamas - At this port, we booked a dolphin experience with AA. Better than RC excursion since island was only 30 min away (vs 60 with RC). My wife loved the contact with dolphin but be didn't buy their pics since we heard they were $70+
Ft. Lauderdale (Port Everglades), Florida - I'm not a big fan of Florida (too crowded but boarding at Ft Lauderdale port went smoothly and efficiently.
Independence of the Seas - I would suggest eating in the dining room as much as possible. The buffet is OK for when you're in a hurry (for an excursion or some other event) but the dining room served wonderful selections and had terrific service.