Qantas...(but besides them, I'd agree with you)
True about Qantas, but Southwest has flown almost 10x the number of flights that Qantas has in its history so it is not exactly apples and apples. Aer Lingus, Finnair, and a couple others have perfect flight records with a few more flights than Qantas, but Southwest has completed several times the number of flights of the best of them.
One could chalk it up to luck, but I am not a big believer in luck.
That's what Dustin Hoffman said in Rainman. Quantas had a perfect safety record, the only airline he would fly on.