Well, Lombok is the only place after you get tired with Bali. It's located to the east of Bali island. You can get there by going on a ferry, it takes about 4 to 5 hours. You can order the hotel and make them send car to pick you up.
I went to Bali last summer. I spent two days there, but after that I crossed to Lombok. This was where the fun begin. The scenery in Lombok was uncomparable to Bali's. It's not too crowded and you can still have lots of fun.
Usually foreigners stay at the senggigi. It is full of resorts and bars. What I like the most is the canoe. You can rent a canoe in senggigi beach for a very cheap price. I used it to sail far away from the shore until the beach guard called us on with boat. Just be careful with the jelly fish though.
Then you have to go to the jewels of Lombok, The gilis. The gilis comprise of three small island: gili terawangan, gili air, and gili meno. The most popular is gili terawangan. FYI, there is no car, motorcycle, or cellular signal there, they really preserve the islands. I suggest you to go to gili terawangan first. You can go there only by a fisherman's boat in about 15-20 minutes. Once you're there, you can do lots of water sports. You can surf, but i suggest you on snorkeling. You can find the resort that rent the gears and the boat. You can use the boat to travel between the 3 islands and they will tell you which spot on the particular island that has the beast view to the coral. They showed me a giant turtle, it was very cool. Be sure to ask around the local people, they are very friendly and willing to help, just be sure you tip them well.
If you want to know about my journey to Lombok, you can read it on my blog. Just be patient with my lack of english.
http://pradeka.blogspot.com/2006/09/lomb…
There are actually lots of beautiful beaches in Indonesia, but other than Bali or Lombok, they aren't very well promoted. They are usually in more remote island with less population. Only those ones who get luck to meet a good guide can go there. The lack of transportation is one of the main reasons. You have to go by foot.
Well, I hope you enjot your holliday.