This is a large limestone peninsula which, bar a sliver of land just south of the airport, would be a separate island. It is rugged and dry, and pre-tourist development this was a real backwater of Bali.
The Bukit (as it is commonly referred to) includes the famous cliff-hanging temple at Uluwatu, a number of Bali's very best beaches including Balangan, and the top surfing spots on the island. As is so often the case, it was intrepid surfers who really opened up the eyes of the world to this part of the island.
The two main towns with strong local communities on the Bukit are Pecatu and Ungasan.
There are number of good white sand beaches on the Bukit Peninsula which many consider the best in Bali:

Balangan. Rated by some as the single best beach in Bali and one which receives relatively few visitors. It takes a bit of finding but from the main junction at Ungasan heading out from Jimbaran towards Uluwatu turn right (west) by Nirmala Supermarket. The road then twists and turns for about 6 km until you reach the beach. Keep following informal signs to "Balangan" or "Balangan Surf" and a west-northwest bearing. This is a stunning beach and well worth the effort required in finding it. There are a few very laid-back warungs on the beach and even a couple of bungalows where you can stay the night.

Bingin. Another white sand beach north of Padang-Padang and south of Dreamland. The beach here is not easy to access as the cliffs are high but the ocean views alone make the visit worthwhile. From the village of Pecatu head towards Padang-Padang and look for informal signs on your right directing you to "Bingin Surf". Proceed down the maze of small roads here, paying a Rp 3,000 toll if the village attendant is there, until you reach the obvious parking areas at the clifftop. There are two sets of steps down the cliff to the beach which are known as the northerly and southerly steps. Don't be surprised if you have to walk through grassy fields with cows and narrow pathways. Women offering massages might chase you from the parking lot. They'll back off after a firm 'no'.

Dreamland. Formerly a very beautiful beach which has been ruined by the adjacent Pecatu Graha Indah "New Kuta" development, sadly it has turned into "Nightmare-land". There are still excellent surfing conditions, especially for intermediate surfers & on days when other breaks are too big to surf. The break goes right & left, is not too shallow and has decent shape. If you do visit this beach, try to imagine how glorious it was before the bulldozers moved in. The entrance road to Pecatu Graha Indah is about 2 km southwest of Ungasan on Jl Uluwatu, and is impossible to miss adorned as it by huge statues and truly massive, intrusive billboards. The entrance fee to use the road down to the waterfront is now not available anymore. Visitors must go through the Klapa Lounge and pay Rp 100.000.

Padang-Padang. A truly lovely beach with a big surf break offshore. Accessed from a stepped pathway on the north side of the obvious bridge 3 kilometres north of Uluwatu Temple heading back towards Pecatu. The white sand beach here is a little bit narrow at the highest of tides but is otherwise very nice indeed.