Turns out my monitor is defective. Fortunately, MacMall is going to replace it with a new one.
At the Apple Store/SOHO, I confirmed that none of their 23" models had my anomalies, and, by the way, none of them had dead pixels either.
So, for what it's worth, this is the first LCD monitor I've purchased from Apple (including a 22" Cinema Display and iBook 12") that had dead pixels, and it turns out to be a defective one.
I wouldn't stress out about it too much. And definitely consider buying your monitor from MacMall. They have been extremely professional in their dealings with me.
