Distance between Towns & Apx Cost

Airport to
- Kuta/South Kuta 3.5km (15min)
- Legian 5-6km (20min)
- Ubud 35-40km (1hr15min)
- Lovina 120km (3hrs)

Kuta Square to
- Legian 2-3km (10min)
- Ubud 32-37km (1hr15min)
- Lovina 115km (3hrs)

Prices based from Ngurah Rai Airport (ph 751011 ex 1454)(south of Kuta) 
referred to internationally as just Denpasar (DPS)

Taxi's - Prepaid Airport Fares
Kuta Beach 11,000 Rp
Legian 16,500 Rp
Denpasar 20,000 Rp
Ubud 65,000 Rp
Cheaper if you get a prepaid taxi from airport to Bemo corner in Kuta, then get a metered taxi or a public bemo to Denpasar or.. Walk It's only 3km to Bemo Corner

Regarding Taxi's
Look for the Light BLUE taxi's, they are very cheap (metred taxi), honest, friendly and air conditioned. All of those who I got, could understand me too, and speak a little English. If you get another taxi, you will need to bargain, or, if they have a metre, ask that they turn it on, it will ALWAYS be cheaper than your bargaining.

In Denpasar, use these 2 Taxi companies:
Komotra - 499449
Bluebird - 7511111

In Kuta just use the light blue or darker blue taxi's, and ensure they turn on the metre.
And in Ubud, you can walk everywhere, else, the street transport guys (Bemo) are your only option, I didn't see any cabs there. If you are going solo like me, then the cheapest way is to just get on the back of someone's scooter/motorbike, if you are going to another region, then car/van is best. I paid 80,000Rp ($13) to get from Ubud to Kuta, and 150,000Rp from Kuta to Ubud.
I think 80,000Rp is a fairer price, they win, you win. It is an 1.5 hr drive afterall.
If your bargaining skills are good, you can hire them for an entire day for 100-130,000Rp. On day trips you will be expected to buy meals for the driver, on over-night trips, you might be expected to pay for their accommodation.

Car Rental
Need International Licence (acquire in your own country first)
Suzuki Katara or Jimny 80,000 Rpm to 120,000 Rp per day - Automatics are Uncommon 
I saw lots of tourists renting scooters/motorbikes, and a few with very shocking injuries. It's about 50,000Rp a day if you don't bargain. You will get hassled by the corrupt police and will have give them money to avoid being locked up. The guy's I spoke with who rented, got hassled by the police nearly everyday, and nearly everyday they would have to pay about 200,000Rp, so if you think about it, unless you are extremely lucky and you go undetected, it costs more to hire your own transport than to hire a driver.