As much as Duncan deserves it for the playoffs, denying Dwight who's an actual center, by puting Duncan out of position would be robbery. Besides Dwight has been a much bigger impact to his team during the regular season than Duncan. IMO Manu has been the MVP for the Spurs this year. Duncan shows up in the playoffs, not so much in the regular season, so lets give credit, where credit is due.
Howard
Garnett (DPOY, biggest turnaround for a team in NBA history, etc..)
Lebron
Kobe
Paul (i hope Williams steals this position next year

)