In Miami we generally stay at the Holiday Inn Port of Miami. It is a $24 ride from the airport. It is directly across from the Bayside Marketplace, which is a nice place to spend a pre cruise evening, lots of shops, restaurants, bars all set around a marina. Bayside Marketplace - Outdoor Shopping Mall in Downtown Miami, Florida Featuring Top Dining & Entertainment
You can get a room overlooking the port if you ask, and watch your ship come in.