I'd actually say Murray. He can hang in rallies with Nole and slice and dice him to death not allowing Nole to go into his safe backboard mode but forcing him to take the initiative in ways he doesn't really like, see their Wimbledon match as evidence. I think their H2H has been really close since Murray became a threat in mid 08 and alot of Nole's wins have been squeakers when he was in top form (Rome 11, Oz 12) or lucky breaks like the 13 Oz Open final or facing Murray on the comeback trail in Miami this year.
I don't think Federer is a bad matchup exactly, he's just a superior player who feels very confident playing against Novak for whatever reason.
Fed is Superior to whom?
People who had no tallness, poor athletic ability or sucked at sports?
99% of the years 2003-2006's players.
Ferrer can beat fed and nadal now. Novak beat fed since 2007 and only choked in the 2007 us open. He was injured slightly and still beat fedal at the 2011 us open.
He will continue to groove and dance versus Murray and fedal, whether you like it or not.
Fedal isn't even a rivalry. It's a borefest of anguish and shank backhands and wta serves from both old men.
The mini djoker son will enjoy watching the 4 fed twins cringe too.