If you were writing a new application from scratch today, and wanted it to scale to all the cores you could throw at it tomorrow, what parallel programming model/system/language/library would you choose? Why?

I am particularly interested in answers along these axes:

1. Programmer productivity / ease of use (can mortals successfully use it?)
2. Target application domain (what problems is it (not) good at?)
3. Concurrency style (does it support tasks, pipelines, data parallelism, messages...?)
4. Maintainability / future-proofing (will anybody still be using it in 20 years?)
5. Performance (how does it scale on what kinds of hardware?)

I am being deliberately vauge on the nature of the application in anticipation of getting good general answers useful for a variety of applications.