Anti Spam Software

[AJ]

My firm is using Exchange 5.5 with World Secure as the MailRelay/Policy
engines. Because of the business practices we are not able to just stop
spam dead with the policy engines/spam filter on the World Secure servers.

We are looking for an anti spam software that will meet the following
criteria

Each individual user/mailbox will have their own quarantine, and allow them
to manage it themselves
Mailbox can set their own level and customization of their spam filters
Quarantines can be set to auto purge/release themselves

If anyone can share what they are using for their anti spamming solution for
their organization I would greatly appreciate. I need to acquire this type
of anit spam utility based on the above criteria,

Thank You,

A.J.