Truly, any will do. But these are listed geographically from South to North. Naples Pier (In the heart of downtown Naples) Vanderbilt Beach (can get crowded, but one of our favorites) Wiggins Pass (A little more of a remote-feel) Barefoot Beach (Similar remote feel)
Lovers Key (State Park entry, very well known across the "Beach highlights" of FL) Fort Myers Beach (This is where Caitlyn spent her weekends in high school/college, the Diamond Head portion is a smidge more peaceful, the Lani Kai portion is much more dirty/party-ish --- pick your poison)
These two locations offer Shops, Restaurants, and Bars of all sorts Mercato is in Naples Coconut Point is in Estero
Those with children might enjoy the Zoo!
If you're looking for more adventure, Google has a plethora of fun activities to suit your interests...because I could go on and on about it...