Web Crawler - Python or Perl?

[disappearedng at gmail.com]

Hi all,
I am currently planning to write my own web crawler. I know Python but
not Perl, and I am interested in knowing which of these two are a
better choice given the following scenario:

1) I/O issues: my biggest constraint in terms of resource will be
bandwidth throttle neck.
2) Efficiency issues: The crawlers have to be fast, robust and as
"memory efficient" as possible. I am running all of my crawlers on
cheap pcs with about 500 mb RAM and P3 to P4 processors
3) Compatibility issues: Most of these crawlers will run on Unix
(FreeBSD), so there should exist a pretty good compiler that can
optimize my code these under the environments.

What are your opinions?