Best Style Whitewater Kayak for Australia

[Aegist]

I'm currently in the market to buy a whitewater kayak. I don't want to rush it though, because these things should last decades (unless I want to upgrade to some super powered new technology to be released in the coming years...), so I might as well get the right one.

So what sort of features should I be looking out for in a kayak for kayaking in Australia?

I expect to be doing a bit of paddling out at Penrith Whitewater stadium (grade 3), and even paddling in the surf just as a form of practice and exercise. I would like to be able to play in the standing waves a bit - try my hand at some surfing - but doing tricks, summersaults, 360s etc aren't that important to me. Mostly I want to be able to hit a grade 4 or 5 rapid (in the future when I am capable of it) and shoot down the rapids without dying.

Any recommendations? What features matter?