@Bratag, of course, but even withing mp3/other lossy formats there are different classes.
People have various needs when talking about music. I would say that for majority mp3 players + any non-totally-crappy headphones is enough. The sound quality sucks, but they don't care. That's just the way it is, we like it or not

I like to really listen to music, not just to have it in background. Thus, I don't use mp3 players, and listen to music at home. But I'm perfectly happy for people who like to listen music on the go, if they are happy with that. And yes, there is sense in talking about quality of mp3, although it's entirely different than talking and comparing quality of two lamp amplifiers.

[edit] so please, don't take this discussion to 'mp3 sucks' (everyone knows it does ), the fact is, that there are mp3 players on the market and people use them. And they are asking how N900 looks in this department.