For convenience, mp3 and streaming would be the winner. Having my entire music collection in my pocket and ready to go is ace, and the ability to make playlists is great too. However, sound quality is compromised unless you're ripping to a lossless format, which means much larger file sizes. The experience of having the physical product, reading through the booklet, looking at artwork etc is something I really value. I grew up with CDs and still buy them regularly.