I'll step up to the chopping block and say I can def. tell the difference of files in a lossless format vs. an MP3 via lame ~224kbps vbr or even at 320. I've even found the differences between Musepack, AAC, and MP3 at similar fairly high bitrates. (Musepack isn't half bad if it does compress your dynamics slightly) This doesn't change the fact that I back up to FLAC but usually listen in ogg and mp3. You lose some noticeable "headroom" when you compress your files, but hey what does it matter when youre enjoying your music out in the real world. But ask those jokers at Stereophile to quantify (i.e. graph) headroom/perceived dynamic changes, and they'll scream "Heretic!" and go running back to their gold remastered discs and their $10,000 a piece speakers and thousand dollar power conditioners. Hell, my golden ears still dont keep me from missing chunks of conversation sometimes. lol.

er...did YOU read TOS #8?

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8. All members that put forth a statement concerning subjective sound quality, must -- to the best of their ability -- provide objective support for their claims. Acceptable means of support are double blind listening tests (ABX or ABC/HR) demonstrating that the member can discern a difference perceptually, together with a test sample to allow others to reproduce their findings. Graphs, non-blind listening tests, waveform difference comparisons, and so on, are not acceptable means of providing support.

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I can count the number of people in my experience who have both claimed to be able to regularly distinguish well-made, ultrahigh-bitrate MP3s from source, and who've fulfilled TOS #8, on one hand. They've all been HA posters, btw (usually involved in codec tweaking). So if you can 'def' hear as well as they do, you won't object to showing some ABX evidence, right?