Here's a few ideas. The thing about Bali is depending on time of year for Australians it is our Cancun - cheap holidays. That crowd certainly exists in and around Kuta. However, get out in the island proper and away from Seminyak (still worth seeing for fun and some great bars) and there are some incredibly interesting and picturesque parts. There are good restaurants in Seminyak worth doing and an active bar scene.
Some highlights to include:
The Rock Bar at the Ayana Resort. On the side of a cliff escalator or steep stairs down. Make a booking or arrive very early and prepare to wait for a seat. Sunset views to die for and certainly worth the effort
Tanah Lot Temple for sunset. Beautiful. Hire a guide there and take the warnings about the monkeys stealing your cell phone and sunglasses right off you very seriously. You will see it happen for sure. Try and make sure it isn't you that ends up the entertainment spectacle
Jimbarin Bay for a pick your fish feet in the sand on the beach rustic dinner. Beautiful, low key and not flash but good food
Ubud is a must - the rice paddies - spend at least two days. Do the cultural bike tour great insights into local life (teeth sharpening, whirling dervishes, family compounds, Hindi life etc). IF you want to do a local thing get sluiced byt the water down the levels of the rice paddies down the hills. Might be too authentic for some and there are snakes. At your own risk and a hoot but the farmers won't love you too much for it...not technically legal
Take a look at Bambuh Inda for a hotel a little off the beaten (not far from the Four Seasons but nothing like a chain hotel and very authentic). Link here:
http://bambuindah.com/
Visit the Monkey Park in Ubud (not a zoo - a park with monkeys everywhere). My advice is don't feed them with bananas the local try to sell them to you. Watch you'll soon see how aggressive they can get
The Don Antonio Blanco Museum is worth a visit. Some of his work is quite erotic. A warning if that offends. Ubud just wander - off the beaten path and you will see so many hidden gems
Also good warm water low danger white water rafting worth doing in Ubud too
For your diving try Gili islands - very beautiful. Check on sea lice conditions. Not dangerous if you run into them but can be annoying. Reef sharks v common nice scuba available too
If you are active try a tour and or climb of the volcanos like Mount Batur. You can do tours too. There is also a couple of hidden villages only accessible by boat with cemeteries that go back eons. Fascinating
It is a Hindu island so please dress conservatively when you go to the temples. The locals are kind but are often offended by what tourists wear. Get your fortune read with the sticks by a monk - fun and worthwhile
If you like cooking there as many cooking courses available too teaching you about their cuisine - they are fun too
Anybody offers drugs _ NO_ death sentence and/or life imprisonment and they get tourists for this frequently. Even if you are non-partaking around someone who is that is trouble. I don't know your age but when my kids go there they are lectured ad nauseaum on this. Weed is there but do not go near it. If you are taking teenage kids please tell them.
Most people do stay on the South but the North is much more authentic. Spend a day or an overnight , hire a driver and go up there. Spectacular and not many tourists. You can keep your main hotel down south and just grab a rustic room for the night in places if you go touring for a song. Cheap accommodation is available right alongside the 5 and 6 star hotels
For a chic hotel/bar try Alilia - you can read about it and a range of other Bali ideas on my wife's blog here:
http://www.batteredorangesuitcase.com/2011/03/resort-hopping-in-bali-part-1-alila-villas-uluwatu/ She will also have some sections there on Hong Kong and a few other places that might interest you
My advice would be slow down, wander/wonder, hire a driver and just explore. Cool place
Honk Kong - the Island and Mid -levels are the better parts. Kowloon - meh a little touristy for me. Just wonder especially the back streets away from the tourists. I spend a lot of time on the China mainland (just got back from there yesterday again) and what you can see in the backstreets of Honkers is equally authentic. Great party town too - go for drinks at the Feather Boa - ask the concierge he should know it... malt ball cocktails - fun cocktail night and usually ends up with a malt ball fight with the ex-pats.
HK is a little edgy at the moment with the protests. I was there the day the UK handed it back to China and the atmosphere there now also feels similar. Everyone is just a little testy. You will not be in any danger but if a protest starts just get out of the way, the Chinese police aren't very delicate
All in all - have fun you have picked a pretty good combo. If you have time or inclination add in Cambodia. Well worth it and if you do let me know and I can give you ideas there.