Planning the next leg of my trip: Sydney to Byron Bay or Brisbane.

Option #1: find a ride with someone via hostel notice boards
Pro: cheap (only have to share the cost of petrol).
Con: you take your chances on who you drive with and if you'll find someone going your way.

Option #2: OzExperience
Pro: Hop on/off options to places that I might not otherwise go see, but are interesting, with a tour guide driver
Con: Young party-seeking backpackers that I might find annoying, stopping in places I might not really WANT to stop in, a bit more expensive since it is like a tour ($226)

Option #3: Greyhound/Pioneer/McCafferty's bus
Pro: cheap ($80), reliable
Con: boring, might miss interesting things, maybe no hop on/off option