Aldridge is a a very good player, among the 20 best in the NBA. The Blazers, as currently constructed, are not in a position to properly utilize Aldridge's talents and win now. For this reason, it is time to trade Aldridge for assets and look to the future.
If the goal is to compete for a 7/8 seed for the next couple of years, and to play .500 basketball, than perhaps it would make sense to keep Aldridge. I would hope that Portland is more ambitious than this. I would hope that the goal is to compete for championships. Aldridge will never have a higher trade value than he does right now. Multiple teams are willing to part with generous packages of future assets in an attempt to win now.
An example is Houston, who have been stockpiling assets in an attempt to lure Howard or Bynum to the team. Should they fail in their efforts, they would still be seeking to acquire a top 20 player such as Aldridge. With a probable lotto pick via Toronto in next years draft, and three top prospects drafted in the 2012 draft to offer, they would make an ideal landing place for Aldridge.
The Blazers will not contend for the next 2 or 3 years. It makes sense to build for a brighter future now, to build a team that could potentially compete in the future. Thoughts?