for example, things like xmms-aalsa can _only_ run with alsa 5 and not alsa9...
use <=media-libs/alsa-lib-0.5.* if this doesnt satisfy you post to Bug 1442
no, not quite, because we don't want the user to downgrade, spanky. this issue was discussed between Daniel and I in irc, and the bug was opened at his request.
this is in portage :D