>Things like Cell and GPUs are all in-order but they're very fast processors.

Actually, I used to think that too. Until we spent some months discussing it (and even making some inquiries to IBM).
You see, a 3.2 Ghz Cell BE IS fast. But how powerful is it?
You need to look at the benches that Andreas re-posted the link to.
Per clock cycle, an out of order PPC is much more powerful then the Cell's core processor.
Trust me, this has been thoroughly hashed over. Many of us had high expectations for the Cell's performance.
But the PPE core turned out to be somewhat weak and programming the SPEs for maximum efficiency was about as easy as juggling running chainsaws.