When gems are graded, weight isn't the only criterion. Cut and color matter a lot, too. Emmy nominators made "gem judgments" of TV's best recently, with Nielsen points, as always, the equivalent of carat weight. Submitted for your approval: Two delightful TV gems that don't pull the ratings of the Emmy-nominated productions, but still have a cut and clarity that make them valuable -- and worth knowing about: Theater Talk and Vine Talk...