There seems to be a misconception about MP3s, particularly that two MP3s encoded at the same bit rate sound the same. The reality being that different MP3 profiles provide better encoding.
I think one of the more common methods of ripping music is just putting the CD in, opening it up in WMP, and expecting the highest bit rate MP3 encode to sound good. It does not. Even before I was big into headphones I could tell the 320kbps rips from WMP sounded drastically worse than a lossless file.
That's not to say I think lossless has a definite improvement over all MP3's. In fact, I can't tell a difference between a good LAME encode and lossless. But of course I keep lossless so as to encode to other formats as I need.
The other big misconception that bugs me is the price=performance, or that a cheap headphone couldn't possibly compete with the big boys. Or the whole "high end barrier of entry" dick waving that goes on here. (Not really a misconception, but something that really irks me.)