When I was in high school, I used to spend the majority of my summer earnings on video games and CDs, but that isn't really an option for me any more. I'm now a college student getting ready to graduate and I just bought a used car which is a bit more important.
I used to preview CDs in the store and buy the ones that sounded good, but it's really hard to judge an album based upon 30 seconds per song, so I've spent a lot of money on CDs that weren't very good. Considering this, and the fact that only a small portion of that money goes back to the band anyway, I feel absolutely no obligation to support the RIAA any further than I already have.
I still will occasionally buy CDs of my favorite artists, but this is because I just want to have them, not because I feel like my support makes a difference to the artist. Overall though, I feel like I'm doing more of a service to the artist by downloading their music and sharing it with my friends who otherwise would have never heard of them, than I would be if I were just buying their CDs, which promotes corporate exploitation of artists and consumers more so than it promotes those who actually deserve it.
Additionally, I'm a musical hobbyist myself, as well as a psychology major with a strong human sexuality and evolutionary musicology influence, so I think I've come to the conclusion quite legitimately that any artist who truly cares about their music and enjoys what they are doing will continue to produce it whether it's economically profitable for them or not.