What should I use to convert FLAC files to AIFF?

I want to play some of my FLAC albums in my car. iTunes on my mac computer will not open FLAC files in order to convert them to AIFF audio files, and my car only plays audio CDs or mp3 files from USB drives (mp3s are out, I can't stand the sound quality).

What file converter product do you recommend for Mac computers? What does everyone use?