Depends...
At home I've got my entire CD collection ripped, along with a "few" additional tracks I've collected over the last four years
. I solely listen to mp3s at home because it's just so damned convenient.
In the car I either listen to my CDs or homemade CDs I've made from those few "additional" mp3 tracks on my hdd.
Can't wait until someone makes a decent mp3/cd player for the car... I will buy one for sure.
l2c