Qld's pretty cool, gold coast is a real authentic oz experience haha. I would never live there no way, but Its cool for trips, beaches are good but I don't know how good it is for skating. I've hit up pizzy a few times on trips which is sick, but I have no idea about street spots. Sydney is cool, kinda easy to get around if you stay in the city, but its pretty expensive for accom in good spots close to everything but the vibes real good and the spots and Waterloo are sick. Newcastle, near Sydney has realllllly good beaches but its a legit hellhole but cool to drive down for a swim, even go to port stephens and hang around there.
Melbournes 10/10 tho, sick spots good to skate around at night and that bluestone is so good to roll around on. Beers are expensive in bars but you can get super cheap takeaways and drink them in a park.