Spam issue resolved? Maybe so...
Rather than deleting my raibledesigns-DOT-com account as I was planning on doing - today I decided to simply start forwarding e-mail from matt-AT-raibledesigns-DOT-com to my GMail account. So far, it seems to be working great. But there's a greater reason it's working well. I also removed the rule that forwarded *-AT-raibledesigns-DOT-com to matt-AT-raibledesigns.com. This seems to have reduced my junk mail by about 80%. As far as I can tell, I was getting about 800 messages per day to [email protected].
According to my ISP, I received around 250 e-mails that were forwarded to GMail, and there were only about 5 that I had to "report as spam" - GMail caught the rest. The downside is that I might be losing some e-mails. For instance, I never receive any notifications from yesterday's comment-ors. Oh well, I don't mind losing a few e-mails here and there. Hopefully I'll get the important ones.