On a recent journey to Bali, I had the most wonderful tour guide, Made Antara. I emailed him prior to my group's arrival to fine-tune our itinerary. He was always prompt and professional in his responses. Because I had a group of 50 with me, I wanted to make sure everything was right. It was a terrific all-day tour, and everyone said it was the best of our journey. Made really knows his island and aims to please. He will customize your tour based on your specific interests; if you do not know what you want, he will make suggestions. He not only handles groups such as ours, but also smaller groups too. He is reasonably priced; of course, prices vary with activities.
Bali Made Tour, http://www.balimadetour.com