How much time do I need to see the Amalfi Coast? is a question I get all the time.
How you spend your time on the Amalfi Coast depends on your interests and travel pace, of course; that said here are the five things I would definitely include on a first visit to the Amalfi Coast. I'd take three full days to do them, mainly because my #1 would take most of a day.
#5. Visit the gorgeous Duomo di Sant'Andrea in the town of Amalfi. If you go in high season, there's a good chance you'll see a wedding taking place. Photo from www.istockphoto.com

#4. Take a boat between Positano and Amalfi (or really, between any of the towns on the coast) to gape at the views of the coastline from the water.
Photo, above, by Sanjay
#3. Have dinner at Don Alfonso's, a (very reasonably priced, considering) three Michelin-star restaurant.
#2. Visit the town of Ravello for the views and for Mamma Agata's fabulous cooking class. Photo, above, of Ravello by Simon.Monk
#1. Since I love hiking and spectacular scenery, my #1 pick for what to do on the Amalfi Coast is to spend 3 hours hiking Il Sentiero Degli Dei, or The Path of The Gods.
If you're interested in hiking it, click here or here for more photos and detailed information. Know, however, that this path is not busy like the Cinque Terre. You can get lost, and you may not run into many other hikers. So bring a map or hire a guide, set off with plenty of water and food, and plan on being out for about 6 hours. And please if you go, send me photos! Photo by NileGuide
Note that these are my picks for what to do on the Amalfi Coast. Add a another day or so to your trip and visit the islands of Capri or Ischia off the coast. Or go up the mainland and spend a few days seeing Naples, Pompeii or Herculaneum.