Artist\Album\Track Number - Track Name
I've had problems with tags, but there's progs out there to solve the tag issue....I think it's up to you to pick a tag convention and have that used, skip it altogether, or offer it as an alternative way of sorting if the individual wants to go that route (again, picking whatever tag convention you wish).
Singles, I also rename them to Artist - Song Name, and file them in a folder titled "Various Artists".
As far as leaving something the way it was ripped, I'm anal about that..every file has bare minimum of Artist and Song Name....all the rest is added, but everything is SORTED via the bare minimums, that way, adding extra sort parameters won't screw up the "general" sort.