|Sunsets in Key West are unparalleled in their beauty.|
Let me tell you about Key West! First, I'd book your hotel early. I think they're all pretty much filled up for awhile because of Spring Break, so if you're looking to go soon, then hop on that! The bigger named chains and such are all on the other side of the island from the action, so keep that in mind. You'll need to drive and fight with parking or get a cab or something. Although, some of them offer shuttles downtown, so you an look into that.
Most of the hotels are cute little boutique experiences. These are little guesthouses and B&Bs and will be walking distance to everything. I've stayed at the Spanish Gardens, The Palms, and The Grand Guesthouse and they've all been good.
Duval Street is like the Bourbon Street and everything happens there. You have to go to Sloppy Joe's -- it's historic, because Hemingway used to write there. I also recommend Hog's Breath Saloon and Irish Kevin's. It's worth stopping at the Smallest Bar in Key West, too. My favorite bar is Flying Monkey's, which is located on the corner of Caroline St. and Duval St. It has Fat Tuesday slushy type drinks.
Key West is known for its sunsets and you can experience those in 2 ways: 1) a sunset cruise. These usually come with unlimited drinks and some munchies. You can get fancy ones that come with full dinner or smaller ones that come with snacks. I like the Fury's Commotion on the Ocean, as it also has a live band. The cruises are 2 hours long. If you don't want to pay for the cruise, head to the town square -- Mallory Square -- and they have a sunset celebration. TONS of people will be here by the water at sunset.
Some touristy spots to hit: The Southernmost Point of the U.S. (stand in the long line for the picture!) There is also a great beach restaurant there at the Southernmost on the Beach hotel called the Southernmost Beach Cafe and Bar. Hemingway's House: You can go in and tour it. I usually just take a picture by the sign. There's also the lighthouse nearby, which is cool if you like lighthouses. End of US 1, Mile Marker 0: The is at some random intersection that I've forgotten. If you are walking it's between Mallory Square and Hemingway, but you'll have to ask someone for the cross streets.
They have at least a couple nice hop on, hop off trolley tours that will take you all around the island and give you the history. It's worth it too take the tour, I think, if you want to learn more about the city. That being said, if you're there a few days you can also walk everywhere. Hemingway House one day, Mile 0 another, Southernmost Point another. The entire place is 4 miles by 2 miles though it seems MUCH larger! Key Lime Pie is a must, and they'll have it everywhere.
Key West is one of my favorite cities! It feels like you're on a Caribbean island even though you're not. There's a very much laid-back, time-is-irrelevant vibe that I just love.