Postgresql 9.1 replication delay
The fact that you have no lines in pg_stat_replication on the master indicates that your streaming replication is not working - and it has instead fallen back on the file based replication, which has more delay.

Check your logs on both master and slave, they should tell you why it's not starting up in streaming mode.

Also, your recovery.conf file is incorrect - you should not be using pg_standby together with standby_mode. That's a leftover from pre-9.0 days.