I've used the marathons and hated them - slow and heavy with no noticeable increase in puncture resistance, milage, or grip. I'm in Sydney but have ridden in and around melbourne. I used to commute 100km a day, now I only do about 65km a day. My favorite tyres are Conti ultra gatorskins in 700c X 28 with Mr Tuffy liners, that's the real secret to puncture resistance.

Once every 2 weeks I take both tyres off and clear out all the stuff that went through the tyres but was stopped by the Mr Tuffy liners. I usually pull from 3 to 10 individual bits from the rear, and occasionally 1 or 2 from the front.90% of it is glass.