Jay Leno made news when he announced that Sarah Palin will be among his high-profile guests when he returns to The Tonight Show next week (aka "The Jaysurrection"). Now David Letterman's lineup for next week pits Mitt Romney against Sarah Palin on Tuesday night -- and the ratings may well provide clues on which probable GOP presidential contender may be most popular. The week's lineup for Letterman's Late Show are: MONDAY, Bill Murray; TUESDAY, Mitt Romney; WEDNESDAY, Jerry Seinfeld and Tom Brokaw; THURSDAY, Tom Hanks; and FRIDAY, Matt Damon. Leno's first week of guests are: MONDAY, Jamie Foxx, Olympic Gold...