I want a good parallel computer

Raph Levien writes about what he wants in a parallel computer

I believe a simpler, more powerful parallel computer is possible, and that there are signs in the historical record. In a slightly alternate universe, we would have those computers now, and be doing the work of designing algorithms and writing programs to run well on them, for a very broad range of tasks.

He gives a nice overview of some of the roads we didn't go down, then talks about possible future directions.