Ponsford, Trumper, Waugh, Ponting, Hayden and Border. I find it hard to split them, but it's out of them for mine.
Ponsfords record is amazing, scoring 7 tons and 6 half tons in 29 matches. To average 48 in Test cricket around the time of the mid 1920's is great. He was one of the first Australian batsmen to finish with an average of over 40 (I have the inside cricket special with all 400 Australian players.) He also averages 65 after 162 first class matches, scoring 47 tons and 43 half tons. That's a fantastic conversion rate.
Victor Trumper is known as one of Australia's most dominant batsmen, who averaged an amazing 39 in Test Cricket playing in the early 1900's which is superb. He also scored over 16000 first class runs with 42 tons. He is known for his aggressive attitude and dominating attacks. He changed the way players batted.
Steve Waugh and Ricky Ponting have been very successful captains, and Ricky Ponting is one of the best batsmen of the modern era, but we can't forget that Steve Waugh took an under performing Australian team, from getting hammered by the West Indian bowlers to being world champions. Whilst doing it, he scored over 10000 runs and averaged over 50. Matty Hayden has been extremely dominating, and has torn attacks apart with brute force, but I wouldn't rank him as high as some of the others I have listed.
Border even had a harder job then Waugh, in the prime of the West Indian fast bowling attack, yet he still scored over 110000 runs which is unbelievable. I am probably leaning to Ponsford or Border here, but I think I'll go with Ponsford, as he was very skillful and managed to be involved in some huge partnerships.