Key West or Naples, Florida?

Naples is a real beach destination and Key West mostly isn't. In Naples, soft pale sand runs the length of the city, from the pier in Old Naples to the wilder dunes of Barefoot Beach and Delnor-Wiggins Pass, and the shallow water is easy for wading and shelling. Watch for stingrays and the odd algae bloom.

Key West's shore is a patchwork: imported sand at Smathers, a local strip at Higgs, and coral rubble at Fort Zachary Taylor, where you need water shoes. What it has is warm, clear water that is better for snorkelling than for lazing on a towel, so time in the water here usually means a boat.

The two eat about equally well, in different registers. Key West is casual and Cuban-tinged: café con leche from takeaway windows, conch fritters, Key lime pie and fish shacks around the Historic Seaport and Bahama Village. Naples dresses up for dinner, with steak, Italian and wine on the terraces of Fifth Avenue South, and keeps its Gulf seafood for the dockside houses around Tin City. Stone crab season and grouper are common to both, and neither is worth the trip for food alone.

Key West has far more to see. Its Old Town is one of the largest historic wooden districts in the country, and the Hemingway Home, the Truman Little White House and the shipwreck collections tell a story of wreckers, writers and presidents that comfortably fills two days.

Naples is a young resort town. The Baker Museum's American art and the Revs Institute's historic racing cars are the highlights, and Palm Cottage gives a glimpse of early settlement, but a day covers it.

Key West is far livelier at night. Duval Street is a long chain of open-sided bars and saloons where you carry your drink from door to door until the small hours, and there is a long-established gay scene at the upper end. It is loud and boozy rather than stylish.

Naples winds down after dinner. A wine bar or piano lounge on Fifth Avenue South, or a tiki bar at sunset, is about as far as it goes, and locals who want more drive to Fort Myers Beach. Neither has much in the way of clubs.

Both put you in good wild country, though Key West's is underwater and Naples' is in the swamp. From Key West, boats run out to the Florida Reef to see rays and turtles, the flats to the north are known for tarpon and bonefish, and the Dry Tortugas offer remarkably clear water and birdlife.

From Naples, the Everglades, Big Cypress and the boardwalk at Corkscrew Swamp are all within an hour, with alligators, wading birds and sometimes manatees, and kayaking the Ten Thousand Islands is the outing to remember. Both are flat with no hiking to speak of, and Naples' wetlands are best in the dry winter.

Naples has more to choose from. The Edison and Ford Winter Estates in Fort Myers, the shelling islands of Sanibel and Captiva, Everglades City and, at a stretch, the Ringling museums in Sarasota are all within reach by car.

Key West sits at the end of the road. The ferry to Fort Jefferson in the Dry Tortugas is a superb day out, and the drive over the Seven Mile Bridge to Marathon has its moments, but after that the options run out quickly.

Naples is much easier with children. Calm, shallow water along sandy beaches, dolphins visible from the shore, Naples Zoo's boat ride past the primate islands and the Golisano Children's Museum fill a week without strain.

Key West has fine moments for children, such as glass-bottom boats over the reef, the butterfly conservatory and the Hemingway cats, but the town's centre is Duval Street, and its drinking culture and the adults-only Fantasy Fest set the tone.

In Key West, you can leave the car behind. The flat, compact Old Town puts the harbour, the sights and the bars within walking distance, and everyone else is on a bicycle. Bring a car into the centre and you will struggle with narrow streets and scarce parking.

Naples is the opposite. The grid around Fifth Avenue South and the pier is walkable, but the rest of the city sprawls along wide roads, and the northern beaches, the Everglades and every day trip depend on a rental car.

Naples is the better place to shop. Fifth Avenue South and Third Street South have jewellers, galleries and linen and resort-wear boutiques under the palms, an open-air luxury mall gathers the designer labels, and outlet malls are half an hour north.

Key West's offer is mostly T-shirts and Key lime soap along Duval, though the Old Town galleries and the hand-rolled cigars that recall its cigar-making past are worth a look on an evening stroll.

Both are costly, so the question is where the money goes. In Key West it goes on rooms in a town with little space to build and on boat trips and the Dry Tortugas ferry, but you save by walking and cycling everywhere. In Naples, winter resort rates and a rental car are the big costs, offset by free beaches and the option of staying inland or in Fort Myers. In both, the hot, stormy late summer is the cheapest time to go.

The two are evenly matched but offer very different evenings. Key West's performance is informal and nightly: jugglers and tightrope walkers at the Mallory Square sunset, drag cabaret, and singer-songwriters in the open-air bars, plus plays at the Tennessee Williams Theatre.

Naples is the more formal stage, with the Naples Philharmonic in its own hall, touring Broadway shows and a professional theatre company downtown. In both, the season is winter and summer is thin.

Neither has a bathing or thermal tradition, and both are easy places to slow down. Naples does it on a larger scale, with big resort spas open to non-guests, golf and a quiet, largely retired population. Key West's calm is on a smaller scale: guesthouse pools in the back lanes of Old Town and the daily pause for sunset, though the party on Duval is never far away.