I prefer the best version I can get. FLAC could even conceivably be an mp3 (and has been done) as FLAC is simply a lossless codec and can cover a range of bit depth/sampling frequency/formats. As long as it's at least 16/44.1 (redbook cd quality) you're good in any case, little advantage to higher resolution files depending on mix/mastering perhaps or wanting to perform processing. Storage costs have become so reasonable it's even possible you could just download a non-compressed file even if you have a lossless compressed file to choose from.....ymmv.
mp3 is one way of a lossy compression file, but some variants like AAC and OggVorbis can do better and even at lower rates....