Concierge.com's insider take:
While the volcanic-black-sand beaches on Bali's north coast (especially Lovina) have attracted a low-key tourism scene, with small hotels and outdoor restaurants catering to budget travelers, the most popular white-sand beaches are in the south. Kuta, on the southwestern coast, is world-famous for its classic surf breaks. It's also a year-round free-form beach party of surfers, hippies, peddlers and masseurs, beer stands, and ice-cream vendors. There are occasional pickpocketing incidents here, but friendly police patrol the beach on bicycles. Just north of Kuta, Legian beach, lined with ritzy resorts and hotels, is much less crowded, with sweeping views of the coastline. But beware: The undertow here is dangerously strong. The southeasterly Sanur beach is delightfully mellow, and popular with Indonesian families on weekends. The grainy golden sand lacks the powdery purity of Kuta's and Legian's, but the morning views of the majestic volcano Gunung Batur more than compensate. The paved walkway along the beach is a superbly romantic setting for an evening stroll.
Farther south, Jimbaran beach, just south of the Denpasar airport, has shallow, calm water that's perfect for families during the day; at sundown, funky fish-barbecue restaurants open, with tables plunked down in the sand. Just south is Dreamland, the ruins of a half-built resort project abandoned after the economic crisis of the late '90s. It's completely undeveloped in any organized sense, but daylight-hour beer joints have opened up, catering to young, mostly European, backpackers. Uluwatu, at the southern tip of the peninsula known as the Bukit, is a prime surfing spot; if you want to hang ten, head to Padang-Padang, an exquisite white-sand beach punctuated by great boulders of volcanic rock, with a fierce break just offshore.