I'm working on a new server built with Unbuntu 10.04, running php-fastcgi, nginx, and memcached.

phpinfo() script loads and works great, same as a test memcached script. For any script using sessions, page load time rockets through the roof.

--- memcached.ini ---
extension=memcached.so
memcache.hash_strategy = "consistent"
memcache.max_failover_attempts = 100
memcache.allow_failover = 1
session.save_handler = memcached
session.save_path = "tcp://127.0.0.1:11211?persistent=1&weight=1&timeout=1&retry_interval=15"

Let me know if you need to see any other configs.