kapitman, a couple of comments:

I drove on the opposite side of the road for the first time about a year ago in the US (from SFO) - I was worried about how hard it would be (I've been driving for 20 years), but I got used to it reasonably quickly! And that was driving a Camaro with extremely poor visibility out of a dark car park at SFO straight onto the freeway at 70 mph! Talk about a baptism of fire! Tried to convince my travel mate he should drive first, but he wouldn't bite! (I'd convinced him we should drive a Camaro and I'd booked it!). Apart from having to remind each other to move over a few times, we shared driving over 5,000 miles without incident.

I've just come back from Cairns with the same mate - we hired a car for 4 days from Avis. It was a near Commodore SV6 (large sports sedan, you might know it a Pontiac G8) that had 7,500 km on the clock - cost AUD 255 for 4 days on a corporate rate with 1 free day. Standard rate was about AUD 330. I prefer to hire from the large well known companies - newer cars with less problems.