The idea behind useing flac is not to play them on your empeg at the moment. If you use flac now, there is never going to be a need to rerip your CDs again, as the copy on your PC will be the exact digital information on the CD (assuming a good rip). You can then encode them all to mp3 now, but when you want to change encoding formats you just reencode everything from the flac files.

Matthew