I will third the bit about staying in Port Douglas versus Cairns. Also, if "quaint" is REALLY your style, consider Palm Cove. However, please don't take the aforementioned comments to mean that Cairns is a bad city--it most certainly is not. Definitely still worth a visit should you make the trip to Oz.

I've gone on Quicksilver as well. Where I goofed was by not taking an outer reef tour. Whether you're novice or super snorkel man, it's worth the longer trip and extra cash to visit the outer reef.

As far as getting to Cairns, DJ is probably the cheapest, although with the introduction of another Branson cash cow, QF has had to lower its prices and adapting their pricing structure as a result. So fares will be competitive. Having flown on both, I'd pick DJ with a seat in the "Blue Zone." It's a much more "fun" airline...definitely a great concept going on down under.