Regarding Postgres Monitoring

Dear Sir/Ma'm,

We are using Postgres  as a database for our application.We are looking for a monitoring tool for Postgres.
Can you please provide any information about which is the best monitoring tool to use which gives good results about the performance of postgres.We have gone through tools like hyperic hq but we would like to know your suggestions on the beast tool.
Any help from your side would make us highly grateful.

Thanks in advance,
Regards,
Sushma Pandey,
Software Engineer.