I would take it even further. Download a good audio converter and transcode one of your favorite 24 bit files to 320kbps MP3 (LAME). I A/B'ed entire albums for hours and could not find a difference.
The benefit often comes from the fact that some producers take more time to master their "high-res" files. Convert the better mastered file to MP3, and see if you can hear the difference between it and FLAC/DSD/etc
hi-res files properly mastered will always sound better and you need not use a hearing tube to appreciate that.
the problem i know there are many low quality Flacs which often are made from upsampling mp3 320kbs which is most dumb thing i heard but quite a few dudes do this :-( you need use trusted quality downloads or use good software to rip your collection.
a well resolving system will also most likely will make audible differences but perhaps not in the way you would expect. i also thought there is no difference if you burn Flac or Mp3 from a music CD. unfortunately for me that was not true and i had huge mp3 collection for which i had to do download and reburn to Flacs. you right Flac will not wow you but in good system you feel better frequency range and blacker space on Flac material compared to mp3, not miles ahead but still noticeable enough for my ears. if you used vinyl setup before you may understand what i mean.
however i agree that there is no audible differences between Flac and Wav files, no difference at all that i could hear in subtleys.
Edited by Gintaras - 8/27/13 at 12:15pm