In 2003 the best team in the NRL won the premiership and that is the Penrith Panthers :D (They will also win the 2010 premiership)
In 1998, the Brisbane Broncos won the NRL premiership.
The Warriors have never won the NRL. They won the minor premiership in 2002.
Melbourne Storm beat the Dragons to win the premiership
Manly Sea Eagles
They have won the NRL premiership twice as of 2010.
The 2006 NRL Grand Final won by the Brisbane Broncos over the Melbourne Storm
Gold Cost Titans
The first premiership in NRL was played in 1908.