That's an old question which gets different answers, and I think it's due in part to different people having more or less discriminating hearing. What you're doing when you listen counts, as you won't notice as much a difference if you're more distracted as in multi-tasking. A better sound card will improve quality, by how much can be a bit subjective. However, you don't have to pay through the nose for a decent sound card either (there are good ones for less than I paid for mine)