hey there, ive pretty much travelled the whole "island"
Have to say that i like dthe east most. Starting from Sydney, the gold coast, byron bay, noosa etc up to whitsunday islands, frasier island and then cairns.
You have lotsa amusement parks around surfers paradise, but i didnt like it, if you want something relaxing and more typical australia go for the other cities. (They call Surfers Paradise the "Paris Hilton" of the east coast)
Too bad you have been to sydney already since it actually ofers everything you need, beaches, shopping, attractions, sightseeing...what you could do is go to melbourne, or perth.