Stop reading this if you haven't yet played the "guess the dissenters" game and for some reason want to.
Neither of the Justices you listed were dissenting.
The Justice that wrote the Opinion of the Court was one that I pegged as a dissenter. This is one of the reasons why I said that I was way off.
You can read the opinions at
http://wid.ap.org/documents/scotus/050606raich.pdf
What follows gives away the show:
Stevens wrote for the Court. I was positive he was a dissenter. He actually sounds like a dissenter during parts of the Opinion.
Scalia was concurring in decision.
O'Connor wrote the main dissent (I had considered her as a possibility for dissent), to which Rehnquist and Thomas joined all but a little personal aside at the end. Thomas also wrote his own dissent.