Thanks Staggers. And, yep, 255/50 R19s.
I have called around Perth, and the prices I am getting per tyre (inc. alignment etc.) are:
Toyo Proxes Sports = $320
Falken = $360
Kumho Ecsta PS71 = $369
Goodyear Eagle F1 Sport = $384
I mean, I'd love to get Michelins... But I have a feeling they're out of my price range. I thought the Toyo was a good price, and came recommended, but from what I've read, they don't seem to last as long and the tyre walls are quite soft, so not ideal for heavier vehicles (although Toyo seems to specialise in heavy vehicles). The XC90 is a heavy vehicle.