Tapas bali
Contributor
@ Madacub: Thanks for the praise, good to hear you enjoy the trip with my team. Keep in touch with the guys on face book. Everyone is getting new & better cell phone to make sure they are on line all the time (except when they are sleeping or diving) 
@ Ward: Trips to most dive sites in Bali actually can be arrange from south Bali whether Kuta, Nusa Dua or Sanur area if you do not mind with the traveling time.
South Bali - Tulamben/Amed: 2.5 hours/way
South Bali - Padang Bai: 1.5 hours/way.
The trip on the way to the dive sites in the morning usually on time while on the way back to South Bali can be one hour longer due to the traffic.
(FYI, Padang Bai is the beach where most dive operator start their trip for Nusa Penida, Mola Mola site & Manta Point)
Except for the North Area (Menjangan), we would not suggest you to do day trip to visit the place. It takes 3.5 hours/way to reach the site.
If you do two day dives/day, you leave South Bali at 7am and get back approximately at 4-5pm (depends on the dive site you choose). That way you will still have a chance to enjoy the "noisy Bali" in the evening.
It is the local people decision to limited the night club building in South Bali only, so if you want to enjoy both dive & city life of Bali, my suggestion would be stay in South Bali.
August is Bali's peak season so you better book the accommodation from now. Some accommodation even already fully booked for August period.

@ Ward: Trips to most dive sites in Bali actually can be arrange from south Bali whether Kuta, Nusa Dua or Sanur area if you do not mind with the traveling time.
South Bali - Tulamben/Amed: 2.5 hours/way
South Bali - Padang Bai: 1.5 hours/way.
The trip on the way to the dive sites in the morning usually on time while on the way back to South Bali can be one hour longer due to the traffic.
(FYI, Padang Bai is the beach where most dive operator start their trip for Nusa Penida, Mola Mola site & Manta Point)
Except for the North Area (Menjangan), we would not suggest you to do day trip to visit the place. It takes 3.5 hours/way to reach the site.
If you do two day dives/day, you leave South Bali at 7am and get back approximately at 4-5pm (depends on the dive site you choose). That way you will still have a chance to enjoy the "noisy Bali" in the evening.
It is the local people decision to limited the night club building in South Bali only, so if you want to enjoy both dive & city life of Bali, my suggestion would be stay in South Bali.
August is Bali's peak season so you better book the accommodation from now. Some accommodation even already fully booked for August period.