Adelaide is a beautiful,too many people bag it, usually the ones who don't leave their own suburb, or couch for that matter...
So i'll be the proud South Aussie and let you know some places of interest.
Some beautiful spots to check out are the Barossa Valley. This attracts tourists from all corners of the globe. If you're into your food, wine & culture, you have to go for a day trip! Only an hour North of Adelaide. Just need to hop on google to look at day tours that leave from the city. Will be gorgeous at that time of year.
The Adelaide Hills have some fantastic spots for wining, dining and scenery. Places like Hahndorf, Sterling. 30 mins east of Adelaide.
Victor Harbor is always nice, beautiful coast line and lovely spots to eat. 1 hour south of Adelaide.
In the city are the botanical gardens, sounds corny, but actually a really pretty spot to stroll through. And obviously we have the usual Museum, Art Gallery etc
The East End markets are a buzz on the weekends and selected week days. It's a true market, that is surrounded by "china town" Endless places to eat.
There is our main shopping strip, Rundle Mall. Would be similar to the main strip in Townsville i'd imagine (sorry haven't been there before) but obviously a huge range of shops, fast food etc etc
The casino is always a go-er on a Fri and Sat night. Always busy and live entertainment.. recommending this as I don't know what sort of scene youare into. Anyone can enjoy the casino.
The weather will be really nice in Oct, beautiful spring days.. A great thing to do is hire bikes in the city (via the council) and do the Torrens River Ride. There is a trail going right along the river, through the city. It's great!
Anyway.... these are a few things off the top of my head. Definitely recommend you to come, as once people actually check out city out they realise it isn't as bad as everyone (inc the locals) say it is.. it's "heaps good"!!