Well, to my knowledge, DTS is a variation of the FLAC codec, so it'd be very easy to download a converter to change it from DTS to FLAC.
I only make an effort to get FLAC files if I REALLY REALLY REALLY love the album. Sorry, not enough disc space otherwise. Like, I have Dark Side of the Moon and Jesu's Conqueror in FLAC, but there is so much great stuff around, what's the point of switching the quantity of quality music for just upping the quality of the sound? Sure, it's an amazing pleasure, FLAC wins. Without any doubt, just, I'd rather have a few more albums covering that space.