Drives should NOT be mounted read-write (they won't be, either, unless the user mounted them him/her self). Read-only is okay; or not mounted at all is good, too.

Afterwards, just reboot the player (cycle the power).

Indeed. And the rebooting bit is important: you can easily scrag your filesystem if you mount it read-only for fsck, then fsck fixes something, then you remount it read-write and do stuff to it. So always either (a) unmount the filesystem to fsck it, or (b) reboot afterwards if fsck made any modifications. For music partitions (a) is easier, but obviously for the root partition (b) is the only way.

Failure to do either (a) or (b) was the bug in the only known alpha release of the player ever to have hosed someone's music partition.

Peter