What Setup Is Best For Large Mailing Lists?

Super_Frosty asks: "I run a large mailing list that has expanded beyond my means. Perhaps you have heard of it - its headquarters is at this site. I currently have about 10,000 subscribers, which I am running from a small group of sad Macintoshes. I can hardly send out the daily message anymore. Anyhow, I can't find anybody who knows how to administer a list this large. I am beginning to have embarassingly close calls with people flooding and spamming the list due to security problems. My hardware can't handle it, and most software packages aren't meant for it, either. Can anybody reccommend a hardware and software solution for this list? Surely, some Slashdotter has administered a large list - I hope!"