The Corniche along the sea front is where the locals take their evening strolls. The large green space of parkland that makes up the Corniche has some great views back into the city, and is most pleasant in the early evening.
The Cultural Foundation is hidden inside a large faceless building, but is a great place to spend a day. It houses a museum, the national library, and art gallery dedicated to Islamic and modern art, and a concert hall where there are performances throughout the year.
The oldest building in town is the Al-Hosn Palace, which was built for the ruler in the late 19th century. The architecture is unique in modern Abu Dhabi, and although it is now used as an archive for the nearby cultural centre, you can walk around the exterior and take photographs.