The economy has been good for a number of reasons. Yes, the Howard government has done a good job in not messing it up, but it's had heaps of outside help. The resources boom for example, has meant that the government has collected greater sums of revenue from businesses. The government does not control that.
We can thank the RBA also for avoiding the recessions suffered by a number of different countries in recent years. They excercised expansionary monetary policy at a time when they would be tempted to raise the cash rate due to their preemptiveness and economic wisdom. The government probably also played a role, but they can't take all the credit.
Furthermore, the Howard government has been excercising a slightly expansionary stance on the economy. Frequent tax cuts and their own jeopardisation of their own established medium-term framework of fiscal consolidation has been partially responsible for interest rate rises. Again, the government does not have full control over the economy, but they have made a contribution to the rises by injecting more money in the economy than was deemed (by themselves back in 1996) to be suitable. Rather than strictly adhereing to fiscal consolidation, they've attempted to win votes by only keeping the budget surplus at 1% of GDP.
It's also not fair to say that higher interest rates under the labour government necessarily was caused by bad economic management. Interest rates currently target inflation, but the role of the RBA has changed. For example, during the Keating government they used interest rates to target external stability. Needless to say, that was a big mistake, but things are obviously different now. The economy is better managed due to better knowledge on the subject and the development of new strategies throughout the world which have been copied by Australia, largely due to their efectiveness (The Kiwis actually came up with the idea to target inflation through the cash rate).
And yes, both political parties have allocated lots of funds for spending, however Rudd has committed less money to initiatives and has had lower tax cuts. Therefore, he would run a higher surplus than Howard, thereby excercising a more contractionary stance on the economy, which is really what it needs.
Lol, sorry. I'm still not over VCE economics...