Matt, I also chose "B-Sides, Remixes, Unreleased," for the same reasons you did... I'd love to see everything that has been released in some format previously, see the light of day on CD.
And I think the radio remixes of "Over My Head," "Rhiannon," and "Say You Love Me," are absolutely essential for inclusion on a remastered 'Fleetwood Mac.'
If they then include some previously unreleased stuff in additon to the b-sides and remixes, then that's terrific... and would be icing on the cake.
Johnny Stew