dbPowerAmp is, far and away, the best CD ripper and format converter available. However, it is a Windows app. Most people looking to convert FLAC to ALAC are doing so because they're using a Mac, and iTunes doesn't support FLAC (or many other audio formats, for that matter). If you're in that category, most people seem to recommend Max:
I've used dbPowerAmp to do the FLAC to ALAC conversions that Ron is asking about. There is a batch mode that makes this very easy to do with many files. For now, I am locked into an Airport Express wireless system so I use Itunes on both Windows and Mac computers to access files on the network.