If you're into big waves, surfing, and beach-life, go to Kuta Beach. The beach is big, wide, and WHITE--the waves invite the surfers in, crashing onto the beach. Even if you don't surf yourself, it's enjoyable just to watch. On the beach you can have massage in the shade of the palms at a very reasonable price, and there are salesmen trying to sell you stuff ALL the time, so if you're into quiet beach-type relaxation, Kuta Beach probably isn't the right place for you.
At the moment, most countries recommend travellers to stay out of Indonesia and therefore Kuta (Bali), because of the bombing on October 12.