What are the best Black Lists to use for email spam filtering?

What are the best Black Lists to use for email spam filtering?

I am an IT tech responsible for my companies鈥?network. We have a large number of "black lists" we can add to query incoming spam on email but what is the best ones to use? If I add too many we may not get emails we should - if I don't use the right ones we will get all the viagra and stock quote junk we don't want. Is anyone familiar with this that could help me?What are the best Black Lists to use for email spam filtering?
Sounds like you are getting the Same problems most admins have.

The key is to filter the Junk, but not to bounce the Content in all cases.

The best practice is to keep the Spam and other Mail in a Cache, or Gateway so that if anyone asks about mail that was sent but did not get through from the outside, then you can release, and either take it off the Black list, or put it on a "white" list.

Refining the list for filtering is not an easy task. and Wait til you get a 10 Million email backlog on the storage servers, and someone asks you to compact the DB... takes a month on some servers