I buy the CD because I like to support the artists I'm buying from,
Go to a concert. They make a whole lot more money that way. The percentage they get from CD sales is minimal.
For some of us, the CD is still the preferred method of buying music. It's tangible, you can play it on the trip home from the store (or in your hotel room since I bought a lot of my music when traveling), and if something happens to the 'puter, you can re-rip the tracks.
For me, downloading the mp3 file is the preferred method of getting music. It doesn't take up physical space, you can play it directly without having to go to a store with a minimal selection and you can get it wherever you have internet access (i.e. everywhere nowadays). And if something happens to the 'puter, you can easily redownload.