As predicted at the beginning of the tournament, the third quarter of the draw (the one where Roddick and Ljubo were the two main seeds) is the quarter of the upsets.
The R16 matches are:
Martin vs Benneteau,
and Ramirez-Hidalgo vs. Ljubo or Monaco.
It's the real chance of all these players to ever make a slam semi-final in their career (and this includes Ivan
EDIT: the bad news is that Rafa's prospective semi-final looks pretty easy now (to compare with Federer grinding vs. a solid opponent like Nalbandian, Gaudio or Davidenko)