I was just wondering if it did any good to take the time?

Nope - I don't do it. It's not worth the time. I filter my email IN, not OUT so whatever remains in the main mailbox is deleted. There are still some that get through the filters, but out of 1500+ spams a day, only about 10-20% end up in a "good" mailbox. :)

What keywords do you use? I have been afraid to do it because I could lose some important emails about Cybernet. You never know what words may be in a companies URL, email addy, or name.....

I only use my name, company name and a few that I know I keep up with (i.e. Delta, the RE company out west, Tupperware, etc.). Most of the spams don't have any of my actual info in the "to" slot, so I base my name filters there and then the company (Delta, Tupperware) names I base on the "from" slot. This is through Eudora.