I can't give you a full blown recommendation, but I did hear the Harbour property is quite nice. It is on the water right before you cross over the bridge to Captiva Island. Which is an ideal location because Captiva is beautiful. If you do stay there, definately head across the bridge to multiple locations in Captiva
I would say if you are not married to Sanibel, head north to Marco and stay at the Marco Island Resort! It is phenomenal!
This is a great resort. We stayed on Sanibel for a week and spent another three nights at the Habour property last year. The resort is located on the water just before the bridge to Sanibel. The sunset views are beautiful and the memory helps us survive the cold New England winters. A day trip to Sanibel is well worth the time. Beaches are awesome. Renting a bike is the best way to get around the island. Explore Ding Darling by car or bike. To get to Captiva you drive across Sanibel. The Bubble Room on Captiva is fun but there are much better restaurants on Sanibel. A day trip to Cabbage Key or Useppa Islands is worthwhile, you will see many dolphins.
Our favorite restaurants:
Doc Fords – especially if you are a Randy White fan
Tall Timbers – great seafood
Island Cow – good for breakfast or lunch
Thistle Lodge Restaurant – nice Sunday brunch (pricey)
Matzaluna’s – good Italian
Sweet Melissa’s – comtemporary menu
Mucky Duck (Captiva) – best place to watch the sunset