Gmail as a spam filter

I came across this great post today about using GMail as a spam filter for your regular email account. The general idea is that you forward all of your email to your gmail address, which filters out the spam and forwards the good stuff back to you. (gmail has a fantastic spam filter built in)

In my case, I use a whitelist for my main email account, which lets through mail only from people I've told it to, and everything else goes to a spam folder. The problem is that if someone is emailing me for the first time, or their email address changes, then they aren't on my whitelist, and they get shuffled into the spam folder even though their email is legit, so I have to check the spam folder periodically to make sure nothing "good" was put in there, and to delete the rest to prevent myself from going over my rater pitiful 40MB mail quota.

So rather than filter everything else into the spam folder, i'm now forwarding everything else to my gmail account, which filters for me and sends the rest back.
That way I don't have to worry about all the spam making me go over my quota, and I'm not forwarding the bulk of my email to GMail, which still has me a little concerned about privacy issues.

We'll see how it works out. I just implemented this about 5 minutes ago.