Federer of course. No contest.
If not for Nadal's absence and injuries (and not becoming an all surface threat until 2008 or 2009 ), Fed would still be searching for the record.
Fed is always the one who benefits the most without having Nadal around.
Murray benefits of course as well. Ferrer can't beat the other 3 guys either much less Nadal. So Ferrer isn't exactly benefitting regardless