In summary, aside from almost nonexistent power-management support and relatively weak wireless support, my HP Pavilion dv2125nr notebook is working great running Red Hat Fedora Linux. On the music/audio front, I've successfully used rosegarden, hydrogen, audacity, pd, snd, sndplay, sox, and other audio-related programs so far. In particular, all of the software examples described at http://ccrma.stanford.edu/realsimple/faust/ were developed, tested, documented, and published entirely on the HP notebook.
The main negative for me with this notebook is the fact that, after less than one year, the battery life fell to less than one hour. It appears to be a Lithium-ion batteries. The warranty on the $120 replacement battery I bought ($140 with CA tax) makes it clear that battery-life is not guaranteed, as if such degradation should be expected.