I wouldn't write-off Brazil from winning the WC, but I think they are slightly overrated in this competition. Yes, they have the Fab Five in Robinho, Ronaldo, Ronaldinho, Kaka and Adriano, but firstly they are probably not all going to play at once and while Robinho has hardly played at Real, Ronaldo has been injured and Adriano's rapidly dipping form and battles with Argentine teammates haven't given him any additional confidence. Their primary wingbacks Cafu and Roberto Carlos should have retired from international football by now; Dida has been rattled more than once this season, Roque Junior (The Brazilian Djimi Traore) is still starting and they are have a huge weight of expecations upon them.
Brazil's strength is definitely in attack as Lucio and Cris are there only consistent performers at the back, but I think this what will make this tournament interesting is that there are a lot of teams who either defensively poor or weak, or have decided to solely focus upon attack.
Italian coach Marcello Lippi has been fretting if Nesta or Canavarro get injured as he feels this Italian team lacks a solid back four; the youthful German defence is still about two World Cups from peaking; Argentina haven't looked defensively sound in friendlies against either England or Croatia; France's aging backline recruits such as Lillian Thuram have been in poor form all season.
I think team's will be attacking more in this tournament because they realize the gap is closing and scoring a goal and sitting back against a team like USA or Korea isn't enough. Also teams like Italy have seen how negative defensive tactics have played a central role in both their defeat to Korea in WC 2002 and their ill-fated game against Sweden in Euro 2004. Look at England's game against Portugal in Euro 2004 in which they sat back after Owen's early goal: it no longer pays to sit back and defend. And naturally the fans are going to want to see free-flowing attacking football and I expect that most teams with their eyes on winning it all will be attacking at will.