Sound was generally just more rich. But yeah the background noise was incredibly noticable. I use SE530's with an audioengine D1 at work since using an integrated soundcard always bleeds motherboard sounds in the audio :/

I read a study a few years back though about how the MP3 encoding artifacts and background noise were so ingrained in culture today that people actually prefer the MP3 encoding artifacts over not having them- Which seems to be supported by this poll. The incorrect choice has a non-trivial lead.