Raph, for Python optimization, take a look at Psyco, the Python specializing compiler. It's been making quite a bit of progress lately.

In general the Python core developers are turning their attention to performance improvements more than they have in the past, so we may have some speedups coming up from that direction as well.

Another interesting development is the Parrot virtual machine. Work on speedups there (JITs, etc) could help any Python that runs on top of it, but that's further in the future.