The only things we watch live (well, close to live - we start them 15 minutes late so we can fast forward through commercials) are Battlestar Galactica and Lost. Everything else is DVRed and watched when we feel like it. So we’re weeks, sometimes months, behind on most shows. So Neilsen doesn’t give a crap about viewers like us, 'cause we don’t watch ads. (Although I read something interesting the other day about ads in fast forward actually leaving a larger subconscious impression than ads at natural speed - sort of a blipvert kind of effect. Sprite was tapping into that with their Sublymonal schtick a while back.)
I think tonight I’m going to lobby for Hex, from a week or two ago (from like three years ago on British tv, I think.) But I might get overruled with yet another *Smallville *or *Supernatural *- we’re pretty far behind on those. If I was forced at gunpoint to chose a show in the OP, it’d be Mystery!.