If you're planning a trip to Bali, I highly recommend hiring a driver for day trips. My wife and I hired a man named Agus (I found him on the internet prior to our honeymoon). It's good to hire a personal driver when you have a whole day that you want to jet around the island from place to place (example: day trip from South Bali up to Ubud) -- it's cheaper and more convenient than taxi. You can rent a car and drive yourself for even cheaper, but people drive a little crazy (safe, but crazy) in Bali and there's literally hundreds of motorbikes flying by you on the streets, not to mention the wandering dogs and chickens (yes, chickens) that randomly cross the road or lay on the side of it.
Anyway... Agus (http://heyboss.biz/) was our driver. He spoke good English and he was extremely knowledgeable about the island. He was an all around good guy.
Agus charges about 380,000 IDR for an entire day -- this is an amazing rate (this is the total charge, including the car rental). His e-mail is gil.agus@hotmail.com, phone is (62) 081.2394.2814. Agus is a really nice guy who needs the work to support his wife and kid.