Actually, 6 of the last 8 teams are former World Cup winners.

There are six former world champions in the quarter-final line-up at the 2006 FIFA World Cup Germany™ - Argentina, Brazil, England, France, Germany and Italy.

Since 1986 when the Round of 16 replaced a second group stage, the highest number of world champions qualifying for the last eight at a FIFA World Cup had previously been four. The full list is:
1986 (24-team competition) Argentina, Brazil, England, West Germany
1990 (24) Argentina, England, West Germany, Italy
1994 (24) Brazil, Germany, Italy
1998 (32) Argentina, Brazil, Germany, Italy
2002 (32) Brazil, England, Germany
2006 (32 teams) Argentina, Brazil, England, France, Germany, Italy The other two teams making up the elite eight in Germany are Ukraine, making their first appearance in the competition, and Portugal, whose previous best achievement was reaching the semi-finals in 1966.

Source: WCoffsite